Add key-frame only decoding for RKMPP #974

Job	Run time
build_portable_linux / Build Portable FFmpeg (amd64)	1h 47m 19s
build_portable_windows / Build Portable FFmpeg (win64)	36m 16s
build_portable_linux / Build Portable FFmpeg (arm64)	1h 41m 49s
build_debian / Build FFmpeg (bullseye, amd64)	54m 14s
build_debian / Build FFmpeg (bullseye, arm64)	14m 33s
build_portable_mac / Build Portable FFmpeg (macos-13, x86_64)	39m 34s
build_debian / Build FFmpeg (bullseye, armhf)	14m 42s
build_portable_mac / Build Portable FFmpeg (macos-14, arm64)	21m 27s
build_portable_windows_clang / Build Portable FFmpeg (CLANG64, win64)	1h 8m 10s
build_debian / Build FFmpeg (bookworm, amd64)	1h 1m 50s
build_debian / Build FFmpeg (bookworm, arm64)	14m 17s
build_debian / Build FFmpeg (bookworm, armhf)	13m 30s
build_ubuntu / Build FFmpeg (focal, amd64)	58m 35s
build_ubuntu / Build FFmpeg (focal, arm64)	14m 46s
build_ubuntu / Build FFmpeg (focal, armhf)	13m 43s
build_ubuntu / Build FFmpeg (jammy, amd64)	53m 8s
build_ubuntu / Build FFmpeg (jammy, arm64)	15m 52s
build_ubuntu / Build FFmpeg (jammy, armhf)	13m 58s
build_ubuntu / Build FFmpeg (noble, amd64)	1h 5m 38s
build_ubuntu / Build FFmpeg (noble, arm64)	15m 31s
build_ubuntu / Build FFmpeg (noble, armhf)	14m 26s
build_portable_windows / Publish Portable Release	0s
build_portable_mac / Publish Portable Release	0s
build_debian / Publish Release	0s
build_ubuntu / Publish Release	0s
build_portable_windows_clang / Publish Portable Release	0s
build_portable_linux / Publish Portable Release	0s
	13h 33m 18s

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