Implement M66 Immediate mode #748

Job	Run time
build (ubuntu-latest, noradio)	1m 53s
tests (ubuntu-latest, tests)	35s
build (ubuntu-latest, wifi)	2m 16s
tests (macos-latest, tests)	33s
build (ubuntu-latest, bt)	2m 6s
tests (windows-latest, tests_nosan)	1m 20s
build (macos-latest, noradio)	1m 27s
build (macos-latest, wifi)	1m 41s
build (macos-latest, bt)	1m 36s
build (windows-latest, noradio)	4m 3s
build (windows-latest, wifi)	4m 30s
build (windows-latest, bt)	4m 20s
	26m 20s

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