Roos-fs-ZIP

User Story:
As a user, I want to convert a lead into a customer while preserving all activity logs, so that to be able to retreve the data and learn about the history of communication.

Acceptance Criteria:

• A "Convert to Customer" button is available in the lead view
• user is promted to cofirm that he wants to proceed
• On conversion:
  --All notes, calls, and emails are migrated
  --A customer record is created
  --Lead data remains accessible through the new customer profile
• the lead history information is available in the customer overview
• Converted customers retain the full activity history
• New notes can be added directly from the customer profile
• Activity is timestamped and shows the author (as in the leads)
• the event of convertion is recorded in the "notes"