Fix coding standards in database schemes. Use DbAdapterFactory in all unit
tests instead of creating own adapters. Fix DbUserBackend and DbStore to use
FETCH_OBJ, instead of FETCH_ASSOC, to handle it consistently in the whole
application. Remove unnecessary table columns from the "account" scheme.
refs #4577
refs #4578
refs #4596
refs #4599
refs #4627
Fix installation instructions for postgresql, the user table is now
'account', as user is a keyword in some rdbms, now catching exceptions
and returning auth failed while logging errors
refs #3769
Set the default database and user to "icingaweb" in the authentication.ini. Add
instructions about how to set up the databases to authentication.ini.
refs #3769