Adds a new -raw_compress lz4 option. lz4 out-performs even snappy_nocrc, and it has knobs to support a range of i/o constraints. However, it has no allocator parameterization, so it cannot be used when drmemtrace is statically linked into the app.
Adds an lz4 reader and tests.
Updates the build docs and the GA CI installation to include liblz4-dev. Fixes the cross-compile jobs to also properly include zlib and libsnappy.
Issue: #5427