Show sheet names at bottom, also ability to rearrange sheets

[me-nkr]

Since the height of the status line is just 1 when there are a lot of sheet names ( or even one comically large sheet name ) the cell details go out of the window width and are no longer visible.

So it would be nice if sheet names and cell details were separated. I suggest keeping cell details at the top and moving the sheet names to the bottom. This will solve the problem mentioned above and as a bonus resemble popular spreadsheet applications.

The ability to rearrange sheets by editing the sc file is mentioned in #852, but being able to do it in the tui with some command could be very nice.