add GitHub Actions CI templates

[rvalyi]

add GitHub Actions for a CI much like the OCA one. It uses the same OCA base image and pretty much the same steps. The difference is that it uses uv instead of pip (faster) and it adds odoo/local-src and odoo/external-src to the addons-path. It uses ak build to fetch odoo/external-src and run the pre-commit and tests on the modules in odoo/local-src. The pre-commit only triggers if there is a .pre-commit-config.yaml file much like in the Gitlab CI. We could templatize this file but it's not done here.

Rational: we need a very light/cheap CI option for small/cheap projects, especially in Brazil. There is often no need for a Runbot experience on "quick start" projects with less than 5k lines of customizations and tests like the OCA ones of local-src is often enough and better than nothing.

cc @hparfr @sebastienbeau @renatonlima

[hparfr]

Hi,

I prefer not put this here in order to keep this already complex template not to broad.

You may be interested by some work I did on https://github.com/akretion/private-addons-repo-template

It's based on oca-addons-repo-template but with an exclude list of modules.
If a module is on this list, it will not be linted, it will not be tested, and its dependencies will not be fetched.

My use case is to put the custom modules on gh with this template and have an oca-esque workflow.