Improve frequency database default edit behavior

[kpreid]

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Two silly missing features that combine to be a bad UI :

1. If no writable database is configured, then the user can create entries which are lost on restart. The UI should hide or disable editing options, instead.
2. The default configuration should include a writable database!

Also, having no UI hints at all about "which database does a record belong to" means that the writable database behavior is extra confusing.

[mathisono]

Option 2 ... I will go ahead and create a new db.