Initial implementation of IP banning

Issues this implementation currently has:

• Identity is an enum, allowing for multiple entries that may shadow one-another, potentially undesirable

• All bans are automatically IP bans

• No way to undo IP bans without manually editing the file

• Order of ban checks in login_provider.rs are a bit weird, needs checking

• By opening this merge request, you agree to release your code and all other changes under the GPL 3 license and to abide by the terms set by this license.

• Migrations have been added if applicable

• Significant changes of this merge request have been added to the changelog.