Cdp-backend

The biggest change of this release is a fix to how we are hashing certain database model keys.

bugfix/use-consistent-datetime-in-hash-generation by isaacna

We are wiping all instances and backfilling the data because of how large this fix is and how little data there is in each instance. In the future however we have already started discussing how to resolve such issues without needing to wipe an instance's data.

**Full Changelog**: https://github.com/CouncilDataProject/cdp-backend/compare/v3.0.0...v3.0.1

This is an early release of v3!

This release is the culmination of multiple years of work in expanding and making our tools and infrastructure more easily deployable and ship with more features.

Thanks to everyone who has contributed along the way, hopefully a v3.0.1 release is just around the corner which we will hopefully consider our "full" release.

Minor changes to the ingestion model, documentation upgrades, fixes and improvements to the database models and validators, and most importantly, and early start for the event gather pipeline. Not fully finished but available for typing.

This is a pre-release developer build of `cdp-backend` created to allow use across repositories (specifically for use in `cookiecutter-cdp-deployment`).

Notably, this pre-release includes the infrastructure setup through `Pulumi` (`cdp_backend.infrastructure.CDPStack`) and all of the database collection management for `Firestore`.