Add support for querying MRs in GLQL

What does this MR do and why?

Add support for querying MRs in GLQL

Allow querying MRs in GLQL. This commit adds support for rendering MRs in GLQL, which is built on top of v0.2.0 of GLQL Rust.

Supported fields to query for MRs include: label, created, updated, assignee, author, milestone, group, project, reviewer, approver, merger, state, merged, deployed, draft, environment.

Verified

0d837716

References

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• Related to #491246 (closed)
• Update dependency @gitlab/query-language-rust t... (!176711 - merged)
• feat: add support for MRs in GLQL (gitlab-org/gitlab-query-language/glql-rust!81 - merged)

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Screenshots or screen recordings

How to set up and validate locally

Feature flag: :glql_integration

Use GLQL to get MRs where you're currently a reviewer:

```glql
display: table
fields: title, assignee, reviewer, labels, state
query: type = MergeRequest and reviewer = currentUser()
limit: 10
```