feat(core/services-azblob): support user defined metadata #1946

Job	Run time
check_clippy	4m 5s
build_default_features (ubuntu-latest)	43s
check_docs	3m 34s
build_default_features (macos-latest)	41s
build_default_features (windows-latest)	1m 58s
build_all_features	4m 57s
build_all_platforms (ubuntu-latest)	2m 55s
build_all_platforms (macos-latest)	2m 30s
build_under_wasm	59s
build_all_platforms (windows-latest)	5m 28s
unit	7m 9s
check_msrv	39s
	35m 38s

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