[FIX][16.0] commissions: Tweak commission permissions

[Shide]

This PR involves several modules in order to have a consistent state across all commission modules.

The goal is to clarify permissions:

• Commision User: Should view agents and Settlements. Are the responsible to tweak commissions (agents and amounts) on sale orders if necessary.
• Commission Manager: Full control.
• Salesman: Only can view commissions on it's own sales.
• Invoicing Commission group: Can invoice settlements and manage invoices (usually related with Accounting permissions).

Commits involved:

[FIX] sale_commission: Better look on Sale Commission Actions
This commit gives a better look to this group and buttons

[FIX] sale_commission: Commission Users can edit agent lines
This Commit is related to allow only to Commission Users the possibility to change or add new Agents to commissions

[FIX] account_commission: Action buttons available for Invoicing permissions
Actions on settlements are available for invocing users only (Commission Invoicing and Account Invoicing).

[FIX] commission: Cancel settlement button only available for group_commission_manager
Cancel button is visible for Commission Users, but clicking it throws an error.

MT-12373 @moduon @pedrobaeza @rafaelbn @yajo please review if you want 😄

[OCA-git-bot]

Hi @pedrobaeza,
some modules you are maintaining are being modified, check this out!