Use filtering instead of hard hiding rows

[zhuj]

It's required to apply row visibility filter based on the value of column 'B' (a multiplier column) with the following values:

• 1 - for estimations - visible;
• 0 - for roles - invisible;
• (empty) - for section columns - visible.

use autofiltering feature for this.

It will make possible to show/hide roles row from standard Excel interface as well as it will make easier to insert new rows in the report (by hand).

[zhuj]

The first implementation (experimental option --filter-visibility) has been implemented.

Unfortunately there is bugs combination in both LibreOffice and XlsxWriter which make impossible to filter by both specific value «1» and blank value «(empty)» at the same time.

Partial fix has been added to the code: it makes the result report file acceptable for Excel and OneDrive, but unfortunately LibreOffice doesn't handle it.

This issue won't be closed until the bug is fixed on XlsxWriter library code.

[zhuj]

Fixed by switching to OpenPyXL. Now it works out of the box + no formula re-calculation is required.