- grass data item provider fixes
- removed QgsProviderMetadata constructor (with std::function / PyObject) due to sip errors (api break)
- reverted DataCapability move to Qgis - back to QgsDataProvider (avoiding api breaks)
- WidgetMode enum documentation
- sipify monkey patching fix
- renamed WidgetMode's "None" to "Normal" value - in python None has special meaning (api break)
For the c++ api dox this expands to "\c nullptr" (the
\c directive indicates a code literal value), and for sipify/Python
it expands to ``None`` (`` is sphinx annotation for literal values)
Makes for nicer dox for both c++ and Python!
