Configure PromQL query for MR to track when deploying

Description

When creating a merge request I'd sometimes like to know the regression/improvements of a certain PromQL query. Now, if one does CD, a deploy will change timing and the like, which I feel should be on the MR, or if one will be created on the PostMR stage/model/entity.

Proposal

Allow a query to be set to track the changes of it after deploying the MR

Documentation blurb

If the user, when creating a merge request, enters a valid PromQL query, the change in values will be displayed after the merge request is deployed.