Feature proposal: Enable custom queries in GitLab panel

Currently in the GitLab panel view, the extension shows a fixed subset of issues/MRs.

This proposal wants to give the ability to the users to define custom Issues/MRs queries to show custom subsets of issues/MRs.

For example, a user could want to define a custom query to get only MRs that have the label "Ready for review", or another query to get only issues created after a certain date.