Move self-hosted dependencies to external folder (#909)

This is in preparation for Clang-tidy and Clang-format.

.gitignore

@@ -14,13 +14,15 @@
 /include/imdebug.h
 
 # /lib/
-/lib/astc-encoder/.gitmodules
-/lib/astc-encoder/Source/GoogleTest
-/lib/basisu/bin_osx
-/lib/basisu/bin
-/lib/basisu/build
 /lib/src
 
+# /external/
+/external/astc-encoder/.gitmodules
+/external/astc-encoder/Source/GoogleTest
+/external/basisu/bin_osx
+/external/basisu/bin
+/external/basisu/build
+
 # /testimages/
 /testimages/*.png
 /testimages/Thumbs.db

.reuse/dep5

@@ -65,53 +65,65 @@ License: CC0-1.0
 ## Licenses of binary files and files from other projects we don't want to
 ## modify
 
+Files: external/astc-encoder/*
+Copyright: 2020-2023 Arm Limited
+License: Apache-2.0
+
+Files: external/etcdec/etcdec.cxx
+Copyright: 2013 Ericsson AB
+License: LicenseRef-ETCSLA
+
+Files: external/fmt/*
+Copyright: 2012-present Victor Zverovich and {fmt} contributors
+License: LicenseRef-fmt
+
 # The JSON format does not support comments for embedded copyrights
 Files: */*.json
 Copyright: 2017-2020 Mark Callow
 License: Apache-2.0
 
-Files: lib/astc-encoder/Docs/* lib/astc-encoder/Test/* lib/astc-encoder/jenkins/* lib/astc-encoder/.gitattributes lib/astc-encoder/.gitignore lib/astc-encoder/.gitmodules lib/astc-encoder/.pylintrc lib/astc-encoder/README.md lib/astc-encoder/Utils/Example/README.md
+Files: external/basisu/Docs/* external/basisu/Test/* external/basisu/jenkins/* external/basisu/.gitattributes external/basisu/.gitignore external/basisu/.gitmodules external/basisu/.pylintrc external/basisu/README.md external/basisu/Utils/Example/README.md
 Copyright: 2020-2021 Arm Limited
 License: Apache-2.0
 
-Files: lib/astc-encoder/.gitrepo
+Files: external/basisu/.gitrepo
 Copyright: 2021 Mark Callow
 License: Apache-2.0
 
-Files: lib/astc-encoder/Source/stb_image*.h
+Files: external/basisu/Source/stb_image*.h
 Copyright: 2017 Sean Barrett
 License: MIT
 
-Files: lib/astc-encoder/Source/tinyexr.h
+Files: external/basisu/Source/tinyexr.h
 Copyright: 2014-2019 Syoyo Fujita and many contributors
 License: BSD-3-Clause
 
-Files: lib/astc-encoder/Source/wuffs-v0.3.c
+Files: external/basisu/Source/wuffs-v0.3.c
 Copyright: 2022 The Wuffs Authors.
 License: Apache-2.0
 
 # We have asked Binomial about REUSE compliance for their repo, see https://github.com/BinomialLLC/basis_universal/issues/165
-Files: lib/basisu/*
+Files: external/basisu/*
 Copyright: 2019-2020 Binomial LLC
 License: Apache-2.0
 
-Files: lib/basisu/apg_bmp.* lib/basisu/CMakeLists.txt lib/basisu/webgl/transcoder/CMakeLists.txt
+Files: external/basisu/apg_bmp.* external/basisu/CMakeLists.txt external/basisu/webgl/transcoder/CMakeLists.txt
 Copyright: 2019 Anton Gerdelan
 License: Apache-2.0
 
-Files: lib/basisu/basisu_astc_decomp.*
+Files: external/basisu/basisu_astc_decomp.*
 Copyright: 2016 The Android Open Source Project
 License: Apache-2.0
 
 Files: tools/imageio/png.imageio/lodepng.*
 Copyright: 2005-2019 Lode Vandevenne
 License: Zlib
 
-Files: lib/dfdutils/vulkan/*
+Files: external/dfdutils/vulkan/*
 Copyright: 2015-2020 The Khronos Group Inc.
 License: Apache-2.0
 
-Files: lib/dfdutils/.gitrepo
+Files: external/dfdutils/.gitrepo
 Copyright: 2019-2020 The Khronos Group Inc
 License: Apache-2.0
 
@@ -201,10 +213,11 @@ Files: the_khronos_group_inc.p12.enc
 Copyright: 2022 The Khronos Group Inc.
 License: Apache-2.0
 
-Files: other_projects/fmt/*
-Copyright: 2012 - present Victor Zverovich
-License: MIT
-
-Files: other_projects/cxxopts/*
+Files: external/cxxopts/*
 Copyright: 2014-2022 Jarryd Beck
 License: MIT
+
+Files: NOTICE.md
+Copyright: 2024 The Khronos Group Inc.
+License: Apache-2.0
+