Allow passing membership_type_id when creating membership payments

When creating membership payments, the membership type id is determined from the the membership through an api call, while there is a big chance that you know the membership type when creating the membership payment.

This adds a big overhead when importing a lot of memberships payments through the api,
and is also unnecessary in most cases when creating memberships payments through the UI

The membership type id is used to update the line_item, until the transition from civicrm_membership_payment to line_item is complete (see CRM-14197)