Allow user to control order of data entry fields to match the register

[dreams-togo]

The grouping of data entry fields is useful when having to choose which ones to display, but when it comes to transcribing, I think these groupings have some undesirable consequences. For one thing, the group labels take up precious space on screen, space which I would like to see given to the image view window instead. Secondly, these groups currently prevent the data entry fields from being visited in an order that matches the register. This increases the tedium of transcribing but it could also increase errors, as it's tricky to transcribe a record that reads left to right with data entry fields that are organised differently. It also defeats the Verify step, because if it's difficult to compare two different visual layouts of the data, that could induce transcribers to simply click the Verify button just to be able to move on. If there were a way to enable users to visit the data entry fields in the same order as the register (which should be allowed to be changed as often as the records in the register itself changes; registers are not always consistent) this would make it easier to transcribe.

[stsccfr]

If data field groups are dropped altogether (see Epic #126) then this issue can also be closed.