D3 config table adding row

[lostcarpark]

Changes to fix issue #134.

For Rooms table, changed insert logic in SubmitEditConfigTable.php to check for empty string in column, and insert NULL instead.

For RoomHasSet, changes using drop-downs were not saving, as label was being inserted when selecting an item. Changed values in editorParams from array of [id: name] keys to [{ label: name, value: id }] objects. The drop-down now correctly inserts the value instead of the label into the grid data.

[LVerhulst4321]

I've put this change into my installation and can confirm that it works.