[RFE] Solution server should make better use of historical data

[fabianvf]

Currently the solution server bases its hint primarily on the most recent accepted change. We should update the hint generation to take into account the full history of successful changes, as well as rejected ones, to form a more complete hint.

[konveyor-ci-bot]

This issue is currently awaiting triage.
If contributors determine this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.
The triage/accepted label can be added by org members.