Add horizontal sorting

[Yaksinikos]

Expected behaviour
Sort my starters and files horizontally.

Actual behaviour
There is just the option of vertical sorting in the drop-down-menu.

Steps to reproduce the behaviour
Right-click on desk and look for sorting.

MATE general version
Mate: 1.20.4

Package version
Brisk Menu Starter: 0.5.0
Mate-Panel: 1.20.5

Linux Distribution
Manjaro Linux 64bit
Kernel: 4.19.30-1-Manjaro x86_64