[IMP] RegForm Angular speedup
[FIX] RegForm: hasPlacesLeft logic
[FIX] RegForm: isBillable logic

Simplified the way we determine if one field is billable as it was
breaking paymentcheck for corner-cases
[FIX] RegForm: Yes/No field mandatory & billable

Mandatory validation works as expected and price is shown per option
when billable
[MIN] Post-rebase fix
[FIX] RegForm: Validation error dialog
[FIX] RegForm: Number field min value as mandatory

Min value doesn't force a mandatory field