Solution Merge: Awaiting Changes status

[tdashworth]

Is your feature request related to a problem? Please describe.
My project has multiple reviewers with many merges going back with comments. It would be nice to add some statuses to aid others visibility of the Solution Merge.

Describe the solution you'd like
I think an "Awaiting Changes" status would help reviewers know that this has been reviewed by someone but changes have been requested. Once the changes are complete then it can go back to "Awaiting Review".

Also, a "Reviewing" or "In Review" status would stop multiple people from reviewing the same solution unintentionally. This status could be bypassed straight to "Approved" to avoid extra steps when it's not necessary and when in this status you should be able to revert back to "Awaiting Review" if you are unable to complete the review.