Give option to name cell in extract formula

[dhoepelman]

In extract formula, when extracting to a single cell a useful option would be to give that cell a name an reference the cell by name instead of by absolute reference.

E.g. =A1*0,19 and =A2*0,19 could extract 0,19 to $B$1, leaving the formula to be =A1*$B$1. It would be better if the user could name the new cell TAX_RATE, so the formula would become =A1*TAX_RATE.

This could be implemented as a separate refactoring "Introduce cell name" which replaces all (absolute) references to a cell with a named range.