Add functionality needed in pittgoogle-user repo

[troyraen]

Prompted by mwvgroup/pittgoogle-user-demos#5
Used in mwvgroup/pittgoogle-user-demos#20

Capturing some to-dos:

• alphabetize init imports if possible. else add code comments about why the order is what it is
• move schema registry manifest -> yaml
• add forced photometry to alert.dataframe
• standardize alert.msg.publish_time to a datetime (update from_cloud)
• publish to TestPyPI and test Switch pgb-broker-utils -> pittgoogle-client pittgoogle-user-demos#20 end to end This doesn't work because then it looks on TestPyPI for other dependencies as well.

Updated changelog:

(copied from CHANGELOG.md)

Added

• Alert and Table classes.
• Registry for alert schemas and GCP Project IDs.
• Alert schemas (Avro) and schema maps (yaml).
• Exceptions: BadRequest and SchemaNotFoundError.
• Types: PubsubMessageLike and Schema.

Changed

• Update PubSub classes.

Removed

• v0.1 BigQuery functions.

[troyraen]

@djperrefort can you take a look at the failing test for Build Documentation? It is complaining about distutils and numpy. The PRs that dependabot has opened (#21 thru #24) appear to have the same failure, so I don't think it's something introduced by this PR.

I did a little bit of Google searching and ended up wondering if we need to restrict to python < 3.12. Seems like we should try updating our explicit dependencies first, but I can't tell exactly what's causing the problem. I tried the more obvious numpy updates, but they didn't work.

[troyraen]

Docs build fixed in #28