ci: migrate to uv

[eyurtsev]

• Update pyproject.toml
• Add uv.lock
• Update workflows and actions to use uv
• Linted a bunch of files
• Had to add ruff lint ignore rules especially for E501 (long lines) to v2 implementation of pgvectorstores -- ideally we can fix those up at some point
• Currently only testing with python 3.12. We should parallelize the test when possible, would require handling the postgres service to accommodate