Add quick sum, average, min, max, count, count non-null of selected values in gridview

[githubuser181226]

In Libre Calc and Excel you can select any cell or cell range and immediately read basic stats or arithmetic expressions in the status bar.
Some of those stats are:

• count all selected values
• count non-NULL values
• sum, average, min and max of all the selected values (ignoring NULL and non-numeric values)

It would be a blessing to have those present somewhere in the UI, perhaps adding another optional toolbar or a status bar for that purpose.

You don't know how many times I just want to filter a table and quickly sum or min/max a selected range.

Please, consider adding simple stats like that.

Thank you.