Variable column width for tabs of info panel

[herb]

Hello Pierre,

I use version 1.10.4 of XnViewMp on Windows 10.

The info panel contains e.g. the following tabs:
- Properties and EXIF: the column width cannot be changed by user
- ExifTool and Favorites: the column width can be changed

I think it is a good idea to allow user to change width of all columns.

Best regards
herb