[ADD] crm: utilize activities for sales teams

[jero-odoo]

Work in progress

Create a new article of documentation that covers a complete use case for using CRM > Activities as a part of regular sales tasks and processes.

Using existing activities documentation, and CRM: Unattended leads report documentation as a jumping off point.

[robodoo]

Pull request status dashboard.

[jero-odoo]

hey @StraubCreative this is ready for review when you have the chance. Thank you!