Support for TimeOnly, DateOnly & Timestamp

[unconverged]

Hi!
This pull requests brings support for time-related columns: TIME, DATE and TIMESTAMP. For TIMESTAMP columns we use DateTime. However, because TimeOnly and DateOnly types are only available since .net 6, we use our own types that can be converted to and from DateTime.

Fix #45

[coveralls]

Pull Request Test Coverage Report for Build 2842292080

• -12 of 105 (88.57%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+3.9%) to 77.652%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
DuckDB.NET.Data/Internal/PreparedStatement.cs	4	5	80.0%
DuckDB.NET.Data/DuckDBDataReader.cs	5	7	71.43%
DuckDB.NET/DuckDBNativeObjects.cs	9	12	75.0%
DuckDB.NET.Data/DuckDBParameter.cs	7	13	53.85%

Totals
Change from base Build 2728373780:	3.9%
Covered Lines:	509
Relevant Lines:	634

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 2940255845

• 63 of 68 (92.65%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+2.8%) to 84.66%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
DuckDB.NET.Data/DuckDBDataReader.cs	9	11	81.82%
DuckDB.NET/DuckDBNativeObjects.cs	0	3	0.0%

Totals
Change from base Build 2934145529:	2.8%
Covered Lines:	582
Relevant Lines:	676

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💛 - Coveralls