[IMP] - account_banking_ccorp: Currency code from company.

Improved method to gather the default currency code from company.
Merge pull request #53 from CLEARCORP-dev/7.0_account_banking_ccorp

[IMP] - account_banking_ccorp: Currency code from company.
[IMP] - account_banking_ccorp: Added improved error messages.
Merge pull request #54 from CLEARCORP-dev/7.0_account_banking_ccorp

[IMP] - account_banking_ccorp: Added improved error messages.
[FIX] - Modified the total sales calculation to used the amount discounted instead of the total amount.
[FIX] - sale_commission: Modified credit calculation and estimated the correponding credit excluding taxes.
[FIX] - sale_commission: Modified wrong field name in credit calculation.
[IMP] - sale_commission: Commissions now manage the state of the related payment.
[IMP] - sale_commission: Updated translation and added domain to filter payments.
Merge pull request #56 from CLEARCORP-dev/7.0_sale_commission_gs

[FIX] - sale_commission: Fixed module to correctly calculate commissions.