Ability to "process" invoice Part 2

Note this was split off of UXPROD-703 as not all stories could be resolve before the Q3 release

Purpose: Users need the ability to close an invoice and have the system generate the appropirate payments against the desired Funds.

Acceptance criteria:

• Move invoice from open to reviewed (User must click a button)
  • Will need a way for invoices to skip the reviewed step for some institutions or specific workflows involving third party systems
• Move invoice from reviewed to approved (User must click a button)
  • Generate Voucher based on invoice
  • Once approved the invoice information can not be updated by a user (Outside of marking as paid or canceled)
• Move invoice from approved to paid (User must click a button, or system updates status)
  • Voucher is marked as paid
  • All associated POLs are marked as "Fully paid" (See next bullet for exception)
  • Subtract amount encumbered by the the Invoice line total however the resulting value can not be negative (will be handled by separate feature)
  • Allow user to select "Do not release encumbrances" for each invoice line (For ongoing orders this will be reversed)
    • If checked POL payment status will not be updated to "Fully Paid"
    • any remaining encumbered value will not be released (will still be unavailable).(will be handled by separate feature)