refactor: Remove metakey concept #2033

Job	Run time
build_all_features	4m 50s
build_all_platforms (ubuntu-latest)	2m 33s
build_under_wasm	45s
check_clippy	3m 58s
build_all_platforms (macos-latest)	2m 23s
build_default_features (ubuntu-latest)	34s
build_all_platforms (windows-latest)	6m 32s
build_default_features (macos-latest)	50s
check_docs	3m 24s
check_msrv	34s
build_default_features (windows-latest)	3m 11s
unit	6m 59s
	36m 33s

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