x11-themes/qogir-gtk-themes: add new port

Qogir is a flat Design theme for GTK 3, GTK 2 and Gnome-Shell.

Supported Desktop Environments:

• Cinnamon
• Gnome-Shell
• Metacity
• Plank
• Unity
• Xfce

https://github.com/vinceliuice/Qogir-theme

PR: 252774
Reviewed by: tcberner
Differential Revision: https://reviews.freebsd.org/D28206