Fix crash during normalization of time zones

[G-D-Petrov]

Reference Issues/PRs

Fixes #1406

What does this implement or fix?

Converts time zone data to string when normalizing with MsgPack. Adds tests to make sure that the crash doesn't reproduce in the future.

Any other comments?

Checklist

Checklist for code changes...

• [ ] Have you updated the relevant docstrings, documentation and copyright notice?
• [ ] Is this contribution tested against all ArcticDB's features?
• [ ] Do all exceptions introduced raise appropriate error messages?
• [ ] Are API changes highlighted in the PR description?
• [ ] Is the PR labelled as enhancement or bug so it appears in autogenerated release notes?

[jamesmunro]

This PR does change the stored and returned timezone data. We should likely hold off for a major version, just as with #1410 Is the original "Coordinated Universal Time" windows example issue urgent in any way?