[Swift] Add support for Timestamp data type

[mgrazianoc]

Describe the enhancement requested

The Swift implementation of Apache Arrow currently lacks support for the Timestamp data type, despite it being available in the base C interface and other language implementations. This creates a significant gap in functionality for Swift developers working with temporal data.

Are you willing to submit a PR?

Yes, I have already prepared a PR implementing this functionality and am ready to submit it once this issue is created.

Component(s)

Swift