Support setting and displaying timezone with the core metrics plugin

[natefoo]

I confused myself and spent too much time this morning looking at the zoneless time displayed under the core metrics for a job, hence this effort to clarify.

When the timezone metric param is unset the behavior remains the same as before. I wanted to get the local server timezone so that we could at least display the name/offset in this case, but doing so is non-trivial using the standard lib. We do have both dateutil (direct) and tzlocal (indirect) as dependencies, but only use dateutil in one place and I didn't want to add another use on a library we could easily rewrite out.

Before / no timezone set
Set to UTC
Set to EST5EDT

For a global server like usegalaxy.org it makes sense to just set it to UTC imo.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[natefoo]

Hrm, I imagined that we had dropped 3.8, but I guess not yet?

[nsoranzo]

Hrm, I imagined that we had dropped 3.8, but I guess not yet?

I think Galaxy 25.0 is a good time to drop Python 3.8, happy to discuss at the Backed WG meeting.

[natefoo]

Converted to draft until 3.8 is dropped.

[jdavcs]

The 4 remaining linting errors are not related to this PR. Merging this, will fix or open issue for linting errors.

[github-actions]

This PR was merged without a "kind/" label, please correct.