EPIC: Add, Delete, Move a TSV7 (TN, TWL)

[birchamp]

This epic is for adding the operations to add or delete rows from TSV7 files like TNs or TWLs. Also included in this is the possibility to change the verse number of a row, essentially 'moving' it from 1 verse to another.

• click plus to add a row
  • popup new row dialog with pre-filled fields including dropdown like tCC
• click minus to delete a row
  • Popup confirmation
• Allow users to edit the reference field to 'move' a row to a different verse.

[kintsoogi]

In case anyone picks up these other issues, I've added some data mutation functionality to translation-helps-rcl to add, delete, move an item