Gracefully handle unsupported qualifiers
This should change nothing for what's currently already
possible in the interface.
However, it is possible that users submit other qualifiers
via custom API calls, potentially even with datatypes not
This patch will:
- add other qualifiers (not defined in $wgDepictsQualifierProperties) to the properties dropdown when editing those properties, so they reflect reality
- display a disabled input field with a "not supported" value for datatypes we don't yet support - thus allowing users to change or delete them (instead of flat out failing to deal with statements that have such content)