chore: make yuzu REUSE compliant

[REUSE] is a specification that aims at making file copyright
information consistent, so that it can be both human and machine
readable. It basically requires that all files have a header containing
copyright and licensing information. When this isn't possible, like
when dealing with binary assets, generated files or embedded third-party
dependencies, it is permitted to insert copyright information in the
`.reuse/dep5` file.

Oh, and it also requires that all the licenses used in the project are
present in the `LICENSES` folder, that's why the diff is so huge.
This can be done automatically with `reuse download --all`.

The `reuse` tool also contains a handy subcommand that analyzes the
project and tells whether or not the project is (still) compliant,
`reuse lint`.

Following REUSE has a few advantages over the current approach:

- Copyright information is easy to access for users / downstream
- Files like `dist/license.md` do not need to exist anymore, as
  `.reuse/dep5` is used instead
- `reuse lint` makes it easy to ensure that copyright information of
  files like binary assets / images is always accurate and up to date

To add copyright information of files that didn't have it I looked up
who committed what and when, for each file. As yuzu contributors do not
have to sign a CLA or similar I couldn't assume that copyright ownership
was of the "yuzu Emulator Project", so I used the name and/or email of
the commit author instead.

[REUSE]: https://reuse.software

Follow-up to 01cf05bc75b1e47beb08937439f3ed9339e7b254

1 files changed, 6 insertions, 1 deletions

diff --git a/README.md b/README.md
index 44679bdfa..7f0461e5e 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,8 @@
+<!--
+SPDX-FileCopyrightText: 2018 yuzu Emulator Project
+SPDX-License-Identifier: GPL-2.0-or-later
+-->
+
 <h1 align="center">
   <br>
   <a href="https://yuzu-emu.org/"><img src="https://raw.githubusercontent.com/yuzu-emu/yuzu-assets/master/icons/icon.png" alt="yuzu" width="200"></a>
@@ -77,6 +82,6 @@ If you wish to support us a different way, please join our [Discord](https://dis
 
 ## License
 
-yuzu is licensed under the GPLv3 (or any later version). Refer to the [license.txt](https://github.com/yuzu-emu/yuzu/blob/master/license.txt) file.
+yuzu is licensed under the GPLv3 (or any later version). Refer to the [LICENSE.txt](https://github.com/yuzu-emu/yuzu/blob/master/LICENSE.txt) file.
 
 The [Skyline-Emulator Team](https://github.com/skyline-emu/skyline) may choose to use the code from these contributors under the GPL-3.0-or-later OR MPL-2.0: [FernandoS27](https://github.com/FernandoS27), [lioncash](https://github.com/lioncash), [bunnei](https://github.com/bunnei), [ReinUsesLisp](https://github.com/ReinUsesLisp), [Morph1984](https://github.com/Morph1984), [ogniK5377](https://github.com/ogniK5377), [german77](https://github.com/german77), [ameerj](https://github.com/ameerj), [Kelebek1](https://github.com/Kelebek1) and [lat9nq](https://github.com/lat9nq)