Plugin development ideas

- [ ] document ideas in an ADR
- [ ] improve development experience with CLJ files
- [ ] shell plugins
- [ ] should atoms in context be supported?
- [ ] validate plugins and fill default values
- [x] file watcher for plugins to reload code for next request
- [ ] plugin for `(merge id-data user-info researcher-status)`
- [ ] plugin for `researcher-status`
- [x] error message change (current supports missing data like `:require-name` and `:require-email`)
- [ ] deftest and unit tests in Markdown files
- [ ] tree-like hierarchical group match for BigPicture groups
- [ ] validate automatically that all extension points are documented