Implement "List requests" API feature
We want to browse the list of submitted add-forge requests so we need a dedicated API endpoint to do so.
Anonymous users should only get info about forge type, forge URL, request status and submission date.
Moderator users should get all info about a request.
Logged in users should also have the possibility to only list their requests.
Migrated from T4027 (view on Phabricator)