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 01cf05bc75

.ci/scripts/windows/docker.sh

@@ -1,5 +1,8 @@
 #!/bin/bash -ex
 
+# SPDX-FileCopyrightText: 2019 yuzu Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
 set -e
 
 #cd /yuzu

.ci/scripts/windows/exec.sh

@@ -1,5 +1,8 @@
 #!/bin/bash -ex
 
+# SPDX-FileCopyrightText: 2019 yuzu Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
 mkdir -p "ccache" || true
 chmod a+x ./.ci/scripts/windows/docker.sh
 # the UID for the container yuzu user is 1027

.ci/scripts/windows/scan_dll.py

@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: 2019 yuzu Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
 import pefile
 import sys
 import re

.ci/scripts/windows/upload.ps1

@@ -1,3 +1,6 @@
+# SPDX-FileCopyrightText: 2019 yuzu Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
 param($BUILD_NAME)
 
 $GITDATE = $(git show -s --date=short --format='%ad') -replace "-", ""
@@ -40,7 +43,7 @@ mkdir $MSVC_SOURCE
 mkdir "artifacts"
 
 # Build a tar.xz for the source of the release
-Copy-Item .\license.txt -Destination $MSVC_SOURCE
+Copy-Item .\LICENSE.txt -Destination $MSVC_SOURCE
 Copy-Item .\README.md -Destination $MSVC_SOURCE
 Copy-Item .\CMakeLists.txt -Destination $MSVC_SOURCE
 Copy-Item .\src -Recurse -Destination $MSVC_SOURCE

.ci/scripts/windows/upload.sh

@@ -1,5 +1,8 @@
 #!/bin/bash -ex
 
+# SPDX-FileCopyrightText: 2019 yuzu Emulator Project
+# SPDX-License-Identifier: GPL-2.0-or-later
+
 . .ci/scripts/common/pre-upload.sh
 
 REV_NAME="yuzu-windows-mingw-${GITDATE}-${GITREV}"