:sparkles: Implement Page bundling and image handling

This commit is not the smallest in Hugo's history.

Some hightlights include:

* Page bundles (for complete articles, keeping images and content together etc.).
* Bundled images can be processed in as many versions/sizes as you need with the three methods `Resize`, `Fill` and `Fit`.
* Processed images are cached inside `resources/_gen/images` (default) in your project.
* Symbolic links (both files and dirs) are now allowed anywhere inside /content
* A new table based build summary
* The "Total in nn ms" now reports the total including the handling of the files inside /static. So if it now reports more than you're used to, it is just **more real** and probably faster than before (see below).

A site building  benchmark run compared to `v0.31.1` shows that this should be slightly faster and use less memory:

```bash
▶ ./benchSite.sh "TOML,num_langs=.*,num_root_sections=5,num_pages=(500|1000),tags_per_page=5,shortcodes,render"

benchmark                                                                                                         old ns/op     new ns/op     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      101785785     78067944      -23.30%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     185481057     149159919     -19.58%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      103149918     85679409      -16.94%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     203515478     169208775     -16.86%

benchmark                                                                                                         old allocs     new allocs     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      532464         391539         -26.47%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     1056549        772702         -26.87%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      555974         406630         -26.86%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     1086545        789922         -27.30%

benchmark                                                                                                         old bytes     new bytes     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      53243246      43598155      -18.12%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     105811617     86087116      -18.64%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      54558852      44545097      -18.35%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     106903858     86978413      -18.64%
```

Fixes #3651
Closes #3158
Fixes #1014
Closes #2021
Fixes #1240
Updates #3757

1 files changed, 36 insertions, 0 deletions

diff --git a/helpers/pathspec.go b/helpers/pathspec.go
index 164d242a0..d5a2c92e8 100644
--- a/helpers/pathspec.go
+++ b/helpers/pathspec.go
@@ -15,6 +15,7 @@ package helpers
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/hugofs"
@@ -31,6 +32,7 @@ type PathSpec struct {
 	canonifyURLs       bool
 
 	language *Language
+	//StatsCounter *siteSta
 
 	// pagination path handling
 	paginatePath string
@@ -38,10 +40,12 @@ type PathSpec struct {
 	theme string
 
 	// Directories
+	contentDir string
 	themesDir  string
 	layoutDir  string
 	workingDir string
 	staticDirs []string
+	PublishDir string
 
 	// The PathSpec looks up its config settings in both the current language
 	// and then in the global Viper config.
@@ -52,6 +56,8 @@ type PathSpec struct {
 	defaultContentLanguage         string
 	multilingual                   bool
 
+	ProcessingStats *ProcessingStats
+
 	// The file systems to use
 	Fs *hugofs.Fs
 
@@ -79,6 +85,11 @@ func NewPathSpec(fs *hugofs.Fs, cfg config.Provider) (*PathSpec, error) {
 		staticDirs = append(staticDirs, getStringOrStringSlice(cfg, "staticDir", i)...)
 	}
 
+	var lang string
+	if l, ok := cfg.(*Language); ok {
+		lang = l.Lang
+	}
+
 	ps := &PathSpec{
 		Fs:                             fs,
 		Cfg:                            cfg,
@@ -91,13 +102,23 @@ func NewPathSpec(fs *hugofs.Fs, cfg config.Provider) (*PathSpec, error) {
 		defaultContentLanguage:         cfg.GetString("defaultContentLanguage"),
 		paginatePath:                   cfg.GetString("paginatePath"),
 		BaseURL:                        baseURL,
+		contentDir:                     cfg.GetString("contentDir"),
 		themesDir:                      cfg.GetString("themesDir"),
 		layoutDir:                      cfg.GetString("layoutDir"),
 		workingDir:                     cfg.GetString("workingDir"),
 		staticDirs:                     staticDirs,
 		theme:                          cfg.GetString("theme"),
+		ProcessingStats:                NewProcessingStats(lang),
 	}
 
+	publishDir := ps.AbsPathify(cfg.GetString("publishDir")) + FilePathSeparator
+	// If root, remove the second '/'
+	if publishDir == "//" {
+		publishDir = FilePathSeparator
+	}
+
+	ps.PublishDir = publishDir
+
 	if language, ok := cfg.(*Language); ok {
 		ps.language = language
 	}
@@ -129,6 +150,11 @@ func (p *PathSpec) PaginatePath() string {
 	return p.paginatePath
 }
 
+// ContentDir returns the configured workingDir.
+func (p *PathSpec) ContentDir() string {
+	return p.contentDir
+}
+
 // WorkingDir returns the configured workingDir.
 func (p *PathSpec) WorkingDir() string {
 	return p.workingDir
@@ -153,3 +179,13 @@ func (p *PathSpec) Theme() string {
 func (p *PathSpec) ThemesDir() string {
 	return p.themesDir
 }
+
+// PermalinkForBaseURL creates a permalink from the given link and baseURL.
+func (p *PathSpec) PermalinkForBaseURL(link, baseURL string) string {
+	link = strings.TrimPrefix(link, "/")
+	if !strings.HasSuffix(baseURL, "/") {
+		baseURL += "/"
+	}
+	return baseURL + link
+
+}