Explicit operator for DuckDBInterval to TimeSpan

[Seddryck]

I was wondering if it would make sense for you if I'd submit a PR to add an explicit operator for DuckDBInterval to transform it into a TimeSpan. I won't implement an implicit operator as the DuckDBInterval is richer than the TimeSpan type (regarding the capability to define an interval based on months/years).

I could also add the reverse operators (from TimeSpan to DuckDBInterval) and in that case, both the implicit and explicit operators.

[Giorgi]

What do you plan to do in cases when the value cannot be converted to TimeSpan?

[Seddryck]

Throw an exception (Argument out-of-range), that's why it should be explicit.

[Giorgi]

@Seddryck I think that makes sense.