Genericize a list of remembered services

[krehera]

Currently we have columns in the DB directly referencing "Fightcade" "Steam" etc. This allows users to tell the bot their username on other services besides Discord. But if a user wanted to add their info for a service we haven't heard of yet, they cannot. Users need to be able to specify the service themselves.

Because users are stupid and/or error-prone, we will need to assist them to make sure they didn't make a typo. We will maintain a list of services and let the user choose from the list. We will also give them the option to request a new service be added. Until I can think of a better solution, this will send a notification to a human (me) and I will add the requested service to the list manually.

this will require creation of a new DB table and moving the data from the users table to that new table.