Use GitHub Actions as CI service (#5602)

* ci: migrate to GitHub Actions

* ci: linux-mingw: use lief for parsing PE files

* ci: fix left-over issues with clang-format check

* ci: workaround libc++ issue on macOS

* appveyor: remove build scripts

* README: add GitHub Actions badge and ...

remove Travis CI and Appveyor badges

.ci/macos/build.sh

@@ -0,0 +1,24 @@
+#!/bin/bash -ex
+
+set -o pipefail
+
+export Qt5_DIR=$(brew --prefix)/opt/qt5
+export PATH="/usr/local/opt/ccache/libexec:/usr/local/opt/llvm/bin:$PATH"
+# ccache configurations
+export CCACHE_CPP2=yes
+export CCACHE_SLOPPINESS=time_macros
+
+export CC="ccache clang"
+export CXX="ccache clang++"
+export LDFLAGS="-L/usr/local/opt/llvm/lib"
+export CPPFLAGS="-I/usr/local/opt/llvm/include"
+
+ccache -s
+
+mkdir build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DENABLE_QT_TRANSLATION=ON -DCITRA_ENABLE_COMPATIBILITY_REPORTING=${ENABLE_COMPATIBILITY_REPORTING:-"OFF"} -DENABLE_COMPATIBILITY_LIST_DOWNLOAD=ON -DUSE_DISCORD_PRESENCE=ON -DENABLE_FFMPEG_AUDIO_DECODER=ON -DENABLE_FFMPEG_VIDEO_DUMPER=ON -GNinja
+ninja
+
+ccache -s
+
+ctest -VV -C Release