MT#7803 Add invoice links and sections.
MT#7545 API: Fix removing old groups from subs.
MT#6425 Typo: restored space (caused to missed localization)
MT#7555 Properly terminate subscribers.

- Write end_huntgroup if a group
- Move numbers to pilot if it exists
MT#7555 API: Terminate instead of delete subs
MT#7793 Insert start_huntgroup event on new group
MT#5879 Make email invoices query simplier.

Remove redundant link through contract_balances to contracts.
Process customer email template and add month and year into invoice data.