feat: Implement `ID` (RFC 2971)

[duesee]

Closes #375

TODO

• [x] Capability::Id
• [x] Allow sending an empty but present list, i.e., A1 ID ()? -> Follow RFC but provide quirk_id_empty_to_nil
• [x] More in #400

[coveralls]

Pull Request Test Coverage Report for Build 7131379001

• 117 of 136 (86.03%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 92.388%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
imap-types/src/command.rs	0	1	0.0%
imap-codec/src/codec/encode.rs	16	34	47.06%
<!--	Total:	117	136	86.03%	-->

Totals
Change from base Build 7130587767:	-0.06%
Covered Lines:	8848
Relevant Lines:	9577

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💛 - Coveralls