Database: Add autoincrement, uniqueness, and sync-writes polyfills

[amotl]

About

Add a few polyfills conceived on behalf of the LangChain adapter, and patches to rdflib-sqlalchemy as well as meltano-target-cratedb. By adding them here, they can be used by downstream applications without needing to install cratedb-toolkit.

Documentation

Preview: https://sqlalchemy-cratedb--28.org.readthedocs.build/support.html

@simonprickett: I would also be happy about your review on documentation syntax/grammar/wording, as I am not an English native speaker. Thanks!

References

• https://github.com/crate-workbench/cratedb-toolkit/pull/59
• GH-76
• GH-77
• GH-83

Backlog

• [x] Software tests.
• [x] Documentation.

[amotl]

@matriv and @simonprickett: Thanks a stack for your excellent reviews. 💯