Add ci scripts for roboleaf CI
After this is submitted, we can point mixed-libc and bp2build CI to
these scripts.
Test: Ran scripts to verify they succeed at head
Change-Id: I7945bb74871e4a42cae382df62984acee212de4e
The code in this directory is experimental. Bazel support for Android Platform is undergoing active development and workflow stability is currently not guaranteed.