What's New in 2.10.0 should show that Vue3 is now in use and where to report bugs with it

[gaktive]

The Vue2 to Vue3 upgrade is a Go now for 2.10.0 but we're aware that various pages & functionality may be broken due to all the components we're migrating.

We should let users know in a prominent way that this has happened. Along with a headline in the release notes, we should update What's New and, to a lesser extent, have a banner upon login after upgrading from 2.9.x that advises that:

1. Vue3 is now in place
2. Link to our repo or a place for people to file bugs if they run into problems

We'll focus on fixing Vue3 bugs for 2.10.1 and we can then remove everything for that subsequent release as we fix things.