Add React.js

This adds it using the in-browser JSX transformer; for better performance we
should use the static one.  But this would require some semblance of javascript
packaging, which we don't have.
Ajaxify scheduling checks page
Merge branch 'main' into ajaxify-scheduling-checks

Conflicts:
	esp/esp/program/modules/handlers/schedulingcheckmodule.py
Add "click title to close" to scheduling checks

This makes them no longer get smaller when opened if there is no data returned
by the check.
Merge pull request #1379 from learning-unlimited/ajaxify-scheduling-checks

Ajaxify scheduling checks