Initializing the server accounts in their own thread (e.g. the
authentication and secure servers) can cause a race condition where the
secure account hasn't been set up yet when authentication configures
`ticket-granting`, causing sometimes crashes on startup.
This has happened on production causing unnecesary restarts. To fix
this, initialize the accounts on the `init` function to ensure they will
always be accessible when needed.
Now database getters do error handling aswell, and in case of any error,
the NEX or GRPC method throws a proper error about it.
There are still some doubts on how to handle errors when a list of data
is processed, so for now skip that element on the list and continue.
Also add some constant errors to do better error handling.
