Operator derived Horreum instance default users.

[whitingjr]

Users deploy Horreum in a cluster. User needs accounts created with sufficient roles. Either a default account or created after deployment.
Currently users are unable to use existing horreum-admin account to fulfil basic tasks. Users are seeing row level security errors raised by PostgrSQL database. Tweaking the roles for horreum-admin account does not allow them to proceed with basic tasks.

2023-03-23 22:16:43,379 ERROR [org.hib.eng.jdb.spi.SqlExceptionHelper] (executor-thread-184) ERROR: new row violates row-level security policy for table "test"
2023-03-23 22:16:43,379 INFO  [org.hib.eng.jdb.bat.int.AbstractBatchImpl] (executor-thread-184) HHH000010: On release of batch it still contained JDBC statements```