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/common/pre-upload.sh

@@ -0,0 +1,6 @@
+#!/bin/bash -ex
+
+GITDATE="`git show -s --date=short --format='%ad' | sed 's/-//g'`"
+GITREV="`git show -s --format='%h'`"
+
+mkdir -p artifacts