Remove validator for "crowd-control.accounts-per-ip.amount"
isSessionAlive() before isRegistered()
Do not double-validate selected hashing algorithm
Fix getAccountPersistence(String) returning null
Use global hashing algorithm in the checkPassword methods if config says so
Use salt when checking passwords with LogItCore if the config says so
Add START_SESSION_FAIL_SELF and START_SESSION_FAIL_OTHERS messages
Rename some messages

This commit renames the following messages
CREATE_ACCOUNT_ALREADY_* -> ALREADY_REGISTERED_*
CREATE_ACCOUNT_NOT_* -> NOT_REGISTERED_*
REMOVE_ACCOUNT_INDIRECT_SELF -> INDIRECT_ACCOUNT_REMOVAL
START_SESSION_ALREADY_* -> ALREADY_LOGGED_IN_*
START_SESSION_NOT_* -> NOT_LOGGED_IN_*
Optimize /login command by making fewer database queries