Implement "Soft Delete" for API Keys

[nelsonic]

At present we have a "hard" delete for all records in our DB which means that when a record is gone, it's gone for everrrr! This is fine from a tidying up perspective but it's terrible from a Security Auditing perspective. If we are going to allow anyone to create an API Key for accessing the dwyl App (e.g: on their localhost) we want some level of accountability. We want people to be able to "soft delete" (i.e. invalidate an API Key) so that it can no longer be used, but we still want to have a record of it in case we need to do any security auditing. see: https://en.wikipedia.org/wiki/Information_security_audit

Todo

• update delete_apikey/1 to set the :status of the apikey to 6 ("deleted")
• Don't show API keys that are "deleted".
• Deal with the fallout from not allowing hard deletes.

[nelsonic]

This is working already in the "Reset API Key" function: