Edit mode and row creation support for Live Data

Live Data now offer a new "Edit Mode", that can be enabled in Live Data instances using a livetable source with the parameter hasEditMode set to true.

This mode offers support for bulk edition of Live Data content (including keyboard navigation), and also the ability to create new rows (which requires also setting the livetable source parameters newRowLocation and newRowNamingStrategy).

Please note that this feature is still experimental and the user experience will be improved in future releases.