Update pycon.registration app
Move registration templates from symposion to pycon

Since all related code is in pycon rather than symposion.
Move registrations tests to subfolder
GET group registration
First pass of group registration POST logic.
Tests for Group Registration post logic
Add group registration permission via migration
WIP
Refine markup & JS; stylize output; add error messages.
Tests for group registration form
Don't send registration emails
Fix CSS typo
Update doc string