Admin\Contacts - create new contact records for existing external users in prod

[andrea-williams]

Describe the task

A clear and concise description of what the task is.

Acceptance Criteria

• write data migration script that creates a new Contact record for each existing external user in our prod database.
• script also includes adding the necessary FK references in the operator_contacts table to connect the new Contact records to their relevant Operator
• script does not create a new Contact record for external users who already appear in the contacts table (query by email address to filter out these)

Additional context

• to be applied on production data around the time that Reg2 is launched in prod
• Or here