[ADD] - added new module partner_payment_average.
[ADD] - partner_payment_average: Added initial wizard and report structure.
[FIX] - partner_payment_average: fixed last payment calculation to include only the last payment and then check if it uses a journal that affects the average.
[ADD] - partner_payment_average: Removed menu from client, added translations and report xml was completed.
[FIX] - partner_payment_average: Changed author.
Merge pull request #64 from CLEARCORP-dev/8.0_partner_payment_average

[ADD] - added new module partner_payment_average.