Mambu Banking Engine

Why:

For Dynamic Loans we currently apply "Payment due" fees at disbursal and not when a repayment becomes due.

This has implications regarding income recognition, since all repayment due fees that will be due in the future are  counted as income when the loan is disbursed, and not when the income is actually being caused (when the repayments become due).

An additional consequence of this is that if the loan is paid off before its normal duration, the fees have to be written off from instalments that didn't trigger any "repayment due" fees, since they were never due to begin with.

Requirements

1. For any new dynamic products created with this fee, apply the repayment due fees when the repayment comes dues
2. Existing accounts which have been already disbursed should be unchanged (since all the fees have already been applied)
3. Create a migration script (private api) which we could offer to client to update existing accounts to remove any unapplied fees so they behave as of the new method as desired (TBD)