multimedia/*x264: Update to 0.165.3223 and transfer maintainership
- Switch to GStreamer's meson branch as it simplifies builds and is faster
- Transfer maintainership to multimedia
- Remove DEBUG, GPAC, OPENCL and PGO options By switching to Meson we can utilize the framework for debug builds GPAC is broken upstream OPENCL (lookahead) has very little advantage now that core count for CPUs are much higher than a decade ago and with x264's limited parallelization. It's also much simplier than x264's other code paths. PGO pulls in GCC with no to little benefit
- Add LTO and OPTIMIZED_CFLAGS options Available only on aarch64 and amd64, enabled by default
Reviewed by: bofh (previous iteration and discussed on Matrix)