MongoDB-based KV store (GSI-2086)

[Cito]

This PR adds the KVStoreProtocol and MongoDB-based providers for that protocol.

For this purpose, the provider module was converted to a subpackage, which now contains the DAO provider in the dao module and the KVStore provider in the kvstore module. Also, the location of the config module was changed (now aligned with akafka provider) and some functions moved to a utils submodule of the provider.

The provider module supports stores with Str, Bytes, JsonObject and Dtos as values.

[coveralls]

Pull Request Test Coverage Report for Build 20850522276

Details

• 152 of 162 (93.83%) changed or added relevant lines in 16 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 92.943%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/hexkit/providers/mongodb/provider/dao.py	7	8	87.5%
src/hexkit/providers/mongokafka/provider/daopub.py	1	2	50.0%
src/hexkit/providers/s3/provider.py	0	1	0.0%
src/hexkit/providers/mongodb/provider/kvstore.py	71	74	95.95%
src/hexkit/protocols/kvstore.py	7	11	63.64%

Totals
Change from base Build 20782490938:	0.02%
Covered Lines:	2792
Relevant Lines:	3004

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💛 - Coveralls