Reusable workflow for precommit hook runs

[JesperDramsch]

We are using pre-commit hooks on anemoi.

These include configuraitons for flaking, linting, and other coding conventions, that would be great to check server-side.

(In fact, we do already, this would just make the workflow reusable.)

[iainrussell]

Hi Jesper, could you also update the README in the root directory with a brief description of this action please?

[JesperDramsch]

Good idea, thanks Iain.