Show Web IDE / Gitpod buttons even for read-only projects

Description

This MR !43352 (merged) revealed that there are some use cases for the Web IDE / Gitpod button that support read only permissions:

• Testing something in a Gitpod container
• Forking the project through the Web IDE to edit

Let's evaluate if we want to show these buttons consistently on the project home page and repository tree view.

Context

From this discussion by @gtsiolis:

suggestion: Now that Web IDE and Gitpod buttons are available on merge requests for all projects including archived projects, does it make sense to also surface the buttons on the project tree controls as the Web IDE button is also available on the file controls for both archived and non-archived projects? This would also remove a small spacing issue in the tree controls when the Web IDE & Gitpod buttons are missing. However, it could be fine to leave this change out of the scope of this MR and discuss this in a follow up issue. Your call! 📞