Spike: Investigate using `uv` to manage envtire project

https://github.com/DiamondLightSource/python-copier-template/issues/245 is an easy win, we would like to make further use of `uv`. Python projects have always required a slightly awkward bringing together of many tools from many vendors, one well-written tool that can manage the venv, tasks and dependencies would be very useful.

For tasks (i.e. a replacement for `tox`) there is an outstanding issue upstream: https://github.com/astral-sh/uv/issues/5903

@coretl to comment on the issues/unknowns that need to be investigated.

## Acceptance Criteria
- A reasonable set of instructions for moving to `uv` is produced

Start by reading linked issue 245 and the upstream uv issue 5903, then inspect the template's current environment, task, and dependency-management approach. Done means producing a reasonable, documented set of instructions for moving the project to uv and recording the relevant issues or unknowns.

Written by the indexing model from the issue text.