Added 'School' Field to onsite reg.

Added 'school' field to onsite student registration as per issue #495.
Field inputs data into 'school' field of studentinfo, but doesn't
fill in 'k12school' field or include the related autocomplete
capabilities. Field is optional.
Merge branch 'main' into belzner_issue_495

Conflicts:
	esp/esp/program/modules/forms/onsite.py
Activate school autocomplete field on onsite reg form

All of the code required for this was there; I just rearranged it so the
k12school information would be saved to the new student's profile at an
appropriate time.
Fix an error in the "old" user search code

I noticed an error came up when generating a list of users (which uses the
old comm panel interface to filter the users).  Some of the code hadn't
been updated for the new UserSearchController.
Merge branch 'main' of github.com:learning-unlimited/ESP-Website into main
Remove old (commented) form code from onsite register template

Thanks to Megan for updating this to clean out a lot of now-unnecessary
template code.