Update all our docassemble packages to use pyproject.toml only

[BryceStevenWilley]

This is for a few reasons:

• opens the way for us to use uv in GitHub actions, a better package manager (in my opinion) that will:
  • let our unit test actions run in half the time, it's just much faster at installing packages (see experiments here: Testing to see if switching to a uv build works with GHA docassemble-EFSPIntegration#276)
  • let us use a lock file for dependencies, which will help with action flakiness (at least for our core packages, don't need one for all packages)
  • potential for running an audit scan routinely: https://docs.astral.sh/uv/reference/cli/#uv-audit
• unifies our developer dependencies with groups (so no more requirements.txt)

An example of a successful switch to pyproject.toml only: SuffolkLITLab/docassemble-EFSPIntegration#298. Would also consider putting the package in the latest docassemble playground and downloading the package, which should generate the correct MANIFEST.in (would have to make sure it doesn't mess up other entries in our pyproject.toml though).

[BryceStevenWilley]

Note: this should just be for our core repos at the moment, i.e. python projects in https://github.com/topics/document-assembly-line.