Added needed enviroment variables for databases to show on panel

[supramaxis]

This pull request fixes the 500 error shown when visiting /api/client/servers/[id]/databases?include=password endpoint An Unexpected error was encountered while processing this request, please try again.

As said by someone over the Pterodactyl Discord:

You now need to specify the salt and length in the compose file.

As generated by the non-dockerized version of the panel, HASHIDS_SALT is a randomly generated 20 digit string with numbers and symbols. HASHIDS_LENGTH is the number 8