Tweak trainee maintainer process

Opened for discussion.

Proposal

• No buddy maintainers.
• Trainees post each review in their trainee issue using a template.
• The maintainers who reviewed the same MR are prompted by the template to give feedback: Please add feedback, and compare this review to the average maintainer review.

Trainees:

• get more regular feedback from multiple maintainers.
• get directed feedback due to the prompt
  • Is this a good idea? If the trainee isn't there yet, it may take time, which could be quite painful after some months. I tried to leave enough room to not force a hard "No, this review is not up-to maintainer level" kind of response.

All maintainers:

• are invested in the process of training new maintainers.
• get manageable chunks of work.
• already have context during their MR review evaluation.
• can make a better overall judgement on the maintainer proposal MR.

In general, this process should result in a trainee issue with everything needed to make a decision, and no pile of work anywhere.

Proposal 2

Same as above but keep buddies for discussing process and progress. This may be more supportive.