Usage of Signup keys

**Is your feature request related to a problem? Please describe.**
You can't see how many keys have been used and when they were used by a user to create an account

**Describe the solution you'd like**
The key management page should also show historical keys and when they were created/used

**Describe alternatives you've considered**
No alternative right npw/ keep using current system

**Additional context**
We will need to modify keys table in database to allow this to work