Support API key expiration
API keys currently never expire. A key can be regenerated to effectively expire it, but there's no way to do so by time. I'm specifically asking...
- Add support for API keys to expire after 30, 60, 90 days, by timestamp, or never.
- Optional. Let the API regenerate or expire keys. Ends up being a one key rules them all situation. Up to debate whether this is a secure approach.