Conversions between DuckDBInterval and TimeSpan

[Seddryck]

As discussed in #112 Close #111

[coveralls]

Pull Request Test Coverage Report for Build 5383170034

• 22 of 24 (91.67%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.06%) to 86.14%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
DuckDB.NET/DuckDBNativeObjects.cs	22	24	91.67%
<!--	Total:	22	24	91.67%	-->

Totals
Change from base Build 5379823364:	0.06%
Covered Lines:	757
Relevant Lines:	874

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💛 - Coveralls

[Seddryck]

Not an expert in SonarQube but I don't think that the build pipeline is failing due to this change

[Giorgi]

@Seddryck Do you think we also need a method on DuckDBInterval that returns if it fits in TimeSpan or not? In case someone wants to filter items without getting exceptions.

[Seddryck]

@Giorgi,

Good call! I'll submit a new PR with your suggestion.