workshop organization workflows for Instructors

In the last update, we stripped out most content on self- and centrally-organised workshops in favor of pointing to existing content about these on our website.

However, the website has a general target audience and does not summarize these events from the perspective of the Instructor. E.g. what is involved in signing up, how are Instructors selected and matched, how registration is handled etc.

It's not totally clear that this content should live *here* but it should live *somewhere* and it is specifically relevant to Instructors, so I am creating an issue here for now.

Review the current instructor-training materials and the existing website content about self- and centrally organised workshops. Identify the instructor-specific gaps around signing up, instructor selection and matching, and registration, then determine where this guidance belongs. Done means the relevant instructor-facing workflow is documented in an agreed location.

Written by the indexing model from the issue text.