[Feature]: Validation action for all PRs

[bratanon]

I propose a feature for:

The integration in general

Describe your wanted feature

To ensure the integrity of our codebase, we occasionally encounter test failures and broken installations due to faulty code being merged into the main branch.

I propose implementing a GitHub Action that runs on all pull requests to validate them. This action would execute all source/service tests to ensure they pass before the code is merged. Additionally, we could set up an automated installation in HA to verify the build. Given the resource intensity of the latter, it might be more efficient to schedule it to run once daily.

This approach would help maintain code quality and reduce disruptions from faulty merges.