CI part 1 - Caching and build speed

[gpmayorga]

Description

We wan to have faster feedback on PRs, for this we've thought of a few options:

1. main branch should be the one to write into the GHA cache, either regularly or on every merge

Research/based on

Off-site open space April 2023

How will this affect the code base

It should allow for faster feedback which at the same time should encourage developers to write smaller PRs

What are foreseen obstacles or hurdles to overcome?

Caching is a little complex and there might be some limitations when modifying the GHA code that may make this task way bigger than it seemed.

Testing this PR will be as hard as it is now until we succeed on caching.

Final testing would have to be done in the main branch after merging this