Create a Filterable data grid based on QDataGrid2

[spekary]

Filtering should not be in QDataGrid2 I think, but rather a subclass, like QFilterGrid.

Not sure it is needed, since DataTables provides filtering just fine.

[olegabr]

I like the @vakopian's idea with search panels. datagrids have no filters, but filter panel can be rendered to provide any filtering capabilities

[spekary]

The current architecture for list connector generation has a filter panel creation now. Currently it uses just one field, and filters everything based on that one field input, but it is easily overridden.

This particular issue is a marker to recreate the filtering capability of the old QDataGrid. The big problem with that implementation is that the code that generated the html for the column filter is in the database node. Data tables has a similar capability, but is limited to what it thinks is in the column. Some significant coding would need to be done to allow Datatables to generate the filters for type lists, or data ranges.