Create Profile and sync_leads: fix bug 1012904

Move choices from UserRegistrationLeadForm to Profile model
Create or update Profile in UserRegistrationLeadForm.save()
Use Rest API and sync updates to salesforce leads
yeah, I thought seriously about doing that each time I wrote `sf = sf or None` but I wasn't convinced it was worth it to save one line. Now that you bring it up though, I might just have to go back and do it. :)