Install instructions have become out of date, especially with introduction of uv #591
Description
What happened?
As part of #579 , I have changed the many pip install commands in the docs to uv sync, but really the docs need a wider restructure.
There are currently installation instructions for each module. But arguably we don't even need to install each module separately any more, and in fact uv will uninstall all other modules if you do that, which was not what the pip install version of the docs had in mind.
Sometimes the intent of the docs is not clear to me in other ways - eg. the pixl_export/README.md formerly had separate prod and dev installation instructions, which conflicts with the fact that in prod the exporter is always installed in a Docker image (except when running pytest directly).
Sometimes the docs ask you to install various dependencies manually (eg. postgres) which I think should now be dealt with by the pyproject.toml.
Do we want to delete instructions for conda and venv and effectively make uv compulsory? Would need to add some docs for how to install python with uv, maybe link to the slab doc.
Relevant log output (optional)
No response
What did you expect? (optional)
No response