EPIC: Migrate k6 discourse forum into grafana community forum

[mellieA]

Summary: k6 has their own discourse forum which we will merge into the existing grafana community forum

This issue is a starting point to assign and track the tasks and questions that we encounter as we research what's involved from the community squads and discourse.

More context in https://github.com/grafana/k6-internal-docs/issues/272 Our tentative completion date is the end of Q1

• [ ] Find out if discourse has tools to migrate the forum
• [ ] What content can be migrated?
• [ ] What happens to the old forum, is there a redirect?
• [ ] How are logins handled for k6 users

[immavalls]

I'm starting to document the requirements, planning, etc in https://docs.google.com/document/d/1Wo27t2fzyc7oQ2TCs5n8vhMBIgDhl4Vl1-OSXNzHtuw/, for internal discussions before we proceed. To update also once we kick off the project with Discourse's migration team.