Use config server for oav config

[jacob720]

Fixes #1448

Link to dodal PR (if required): DiamondLightSource/dodal#1748

This PR also removes all OAV test config from the repo. Instead it is read from a mocked config server, and all tests in mx-bluesky and dodal are now using the same config. Tests have been changed to reflect this.

(remember to update pyproject.toml with the dodal commit tag if you need it for tests to pass!)

Instructions to reviewer on how to test:

1. Confirm config is read through the daq-config-server

Checks for reviewer

• Would the PR title make sense to a user on a set of release notes