Rows/columns insert/delete

[rpeshkov]

Add commands for inserting/deleting rows/columns.

In Emacs it's done via following shortcuts:
Insert row: M-S-Down
Delete row: M-S-Up
Insert column: M-S-Right
Delete column: M-S-Left

For showcase refer to wiki

[huyz]

I did find commands for moving columns and rows. I figure these operations involve insert and deletion. Yet, I can't find the commands for insert/delete. 🤔