Login to microsite domain redirect to microsite group overview

[ekes]

We want anyone who logs into a microsite to be redirected to the main dashboard for that microsite, not end up on their user page.

Acceptance tests:

• [ ] Log in to microsite as a microsite admin or microsite editor
• [ ] Be redirected to the microsite dashboard.

[ekes]

https://github.com/localgovdrupal/localgov_microsites_group/pull/34#pullrequestreview-977060859