[Feature] Transform deleted MEMBER accounts to LOCAL accounts

[Yoronex]

What would you like?

See title.

Why is this needed?

In #350, we discuss the plans on how to handle people leaving GEWIS. However, a few years after their leaving, they might come back to drink some beers (for example at an ADA VrijMiBo). These people want to use SudoSOS, yet their accounts no longer "exist". SudoSOS might still have this information, so it is nicer to reuse an "old" account than to create a brand new one, as this avoids duplicates.

How could it be implemented?

We should implement a workflow that transforms MEMBER users that are deleted into LOCAL users, so they can still use SudoSOS as external users (and with their old GEWIS ID at the POS).

Note that LOCAL accounts should not be able to go into debt, so this should be disabled during the transformation.

Other information

No response

[SvenMokveldje]

This feature has already been requested in #106, we might want to remove one?