Add new workflow for build/CD on PRs

[AndreasBurger]

also add trust-helper, a workflow that auto-labels PRs based on team-membership of the creator (as was set up via WHD previously)

[kon-angelo]

I think we have a "competing" script for the head-update that can probably be coalesced in this one

[kon-angelo]

Can we also run build on master and release branches push ?

[github-actions]

The overall change involves updates to GitHub workflows concerning automation of build processes and managing pull request trust. The modifications optimize workflow execution by adjusting triggers and permissions, while introducing a new helper workflow to manage trust for pull requests, thereby potentially streamlining the CI process and enhancing the security checks around pull requests.

Walkthrough

• Refactor: Transition of the trigger from push to merge_group for build workflow, indicating a focus on optimizing CI triggers for specific branches.
• New Feature: Introduction of pullrequest-trust-helper.yaml, which configures access controls for pull requests, ensuring automated trust checks based on defined teams, improving security and collaboration.
• Chore: Reorganization and renaming of workflow configuration files to enhance clarity and maintainability.

_{Model: gpt-4o | Prompt Tokens: 464 | Completion Tokens: 157}

[kon-angelo]

/lgtm