Deploy docs using GitHub Actions and not through a branch (in the template)

[Saransh-cpp]

Which Section of the Documentation Needs Improving?

Deploying docs using the gh-pages branch is a bit "outdated" and also difficult to showcase (failure - check permissions - rerun workflow - set branch for deploying - works)

What Can be Improved About This Section

We should use https://github.com/actions/deploy-pages instead (inside the template - https://github.com/UCL-ARC/python-tooling/blob/main/%7B%7Bcookiecutter.project_slug%7D%7D/.github/workflows/docs.yml).

How to Improve This Section

No response

[matt-graham]

@Saransh-cpp have you already started working on this? I was going to do a quick PR to resolve this and #574 but just noticed you're assigned so don't want to usurp you!