Randomly Generates a username for unclaimed username

[luchiago]

Related to: #165 Using a little script and/or Faker package to do this. My idea is when a person wants to contribute with the new website, it has to run the generator first, which will test if it exists, and if not the person can put in the JSON. If you guys let me I can send a pull request

[kilianplapp]

I don't think this is a big enough of a problem to be fixed, all it takes is adding a few numbers or some other obscure change, its really not that hard.

[ghost]

It's happened in #165

[cclauss]

import time ; f"user{time.time_ns()}".rstrip('0') --> user1657191108413085

[sdushantha]

This has now been added to Sherlock last week :)