add a pre-commit image

Add a new image which packages pre-commit and associated dependencies. Over time we may find we want to add additional dependencies to the image such as node, etc. We'll probably have to re-visit the config as the use of pre-commit grows.

A successful pipeline run can be found at https://gitlab.developers.cam.ac.uk/uis/devops/infra/dockerimages/-/jobs/965214

The image will be pushed to registry.gitlab.developers.cam.ac.uk/uis/devops/infra/dockerimages/pre-commit with the labels "3", "3.3", "3.3-py3.11" and "latest" which allows us to add additional pre-commit versions as time goes on.

Closes #69 (closed)