BISERVER-10699 Lost functionality from 4.8 -> 5.0: Need alternative way of customizing startup behavior and settings to PUC

The startup behavior can now optionally be altered by User Settings instead of just pentaho.xml system settings.  This means that we can change startup behavior/settings globally, by tenant and by user, in that order of precedent.

This commit also fixes an issue with the AboutCommand's null check for the user-console-revision.