Store usernames in lowercase

[ItsOnlyBinary]

Hopefully i got all the places that are needed.

also unsure if i should remove the 'LIKE' from the where clauses as i think its now redundant

[prawnsalad]

Adding it here as it sets the username value will cover cases where a user is created via the model factory

kiwibnc/src/libs/dataModels/user.js

Line 17 in 34ad5bc

set username(newVal) { return this.setData('username', newVal); }

[prawnsalad]

As mentioned in #kiwiirc:

• Include a data integrity function that runs on startup that checks for any usernames containing uppercase letters (where lower(username) != username)
• If any are found, throw out an error explaining the issue and what to do before exiting.
• Include a config option skip_data_integrity_check, true/false. Defaults to false.