Filtering of merge requests by deployments data

What does this MR do?

This adds support for filtering merge requests by the environment name and deployment times, in addition to the existing support of filtering merge requests by a deployment ID. This means you can now get merge requests that match an environment name, deployment ID, or are deployed before/after a given date and time. These filters can be combined as well.

Filtering merge requests by deployments data makes it easy to see what has been deployed, and when. In addition, you can apply all the other merge requests filters such as a list of labels to filter by.

See gitlab-com/gl-infra/delivery#1246 (closed) for more information.

Feature flag rollout issue: #267561 (closed)

Screenshots

Filtering by environment	Filtering by date	Filtering at the group level

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.

TODO

• Clean up finder code/WHERE EXISTS
• Add frontend filter support (with a date/time picker?)
• Add documentation
• Add API parameter support
• Add screenshots
• Hide all this behind a feature flag