Add an optional "Projects" section where members can list things they've worked on during 10 weeks to the Introductory Evaluations form

I mentioned this during History discussion and Devin recommended making a PR, but I thought I'd see if anyone had any thoughts on this first.

No file, test, or entry point is named in the issue. Locate the Introductory Evaluations form and review how its member fields are rendered and saved; done means an optional Projects section lets members list work completed during the 10-week period without affecting submissions that leave it blank.

Written by the indexing model from the issue text.