Scope of GNOME MRU

In reviewing a gjs SRU just now, I noticed that it didn’t link to the test plan @jbicha wrote up above and nor was that linked from the main GNOME exception documentation. So I’ve adjusted these.

I’ve also written up my idea of how we’ve agreed test plans and approvals will work. @jbicha please could you review?

On the gjs test plan itself, it looks fine to me but I’m not particularly familiar with the area. @raof please could you review it?