[12.0][IMP] - Add pause button to contract line
[IMP] - Add state filed in contract line form
[FIX] - stop don't change date_end for finished contract line
[IMP] - Change contract line buttons visibility
Add renewal process with termination notice
[FIX] - don't consider stop_date If it is after the contract line end_date
[IMP] - consider more cases in stop_plan_successor
[IMP] - cancel upcoming line on stop
[IMP] - Chnage next invoice date on un-cancel
[IMP] - Post message in contract on contract line actions
[IMP] - check contract line overlap