feat(core/services-azblob): support user defined metadata #1938

Job	Run time
check_clippy	2m 31s
build_default_features (ubuntu-latest)	46s
build_default_features (macos-latest)	35s
check_docs	2m 30s
build_default_features (windows-latest)	1m 58s
check_msrv	32s
build_all_features	2m 30s
build_under_wasm	51s
build_all_platforms (ubuntu-latest)	2m 31s
unit	2m 31s
build_all_platforms (macos-latest)	2m 21s
build_all_platforms (windows-latest)	2m 22s
	21m 58s

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