add db_all_cred methods to authbrute

adds 3 methods to add db_all_creds functionality back to
the loginscanners
call new prepend cred methods

add method calls o all the lgoinscanner modules
so that they call the prepend_db_* methods as approrpiate
these methods automatically check to see if DB_ALL_CREDS was
selected
Merge branch 'master' into feature/MSP-11162/db-all-creds
check if database is connected first

wooops
Land #3746, reinstate DB_ALL_CREDS