Merge user profiles

[renatobellotti]

Possible roadmap to the solution:

• Get a list of all accounts that have the same email address.
• Inactive all accounts but the one that has been most recently logged in to.
• Set all foreign keys that point to an inactivated account to the active one.
• Set the "account created" time to the oldest value among all duplicate accounts.
• If the surviving account misses information that is present in other accounts, copy them.
• If information in the different accounts is contradicting: Mark for manual processing.
• Delete the inactive accounts.

Additional step: Create a list of inactive orphan accounts. If such accounts exist, think about what to do with them. If not: Have a nice evening.