Add better use of keyboard shortcuts

[timlau]

current upstream has better use of keyboard shortcuts

• Ctrl - F for seach
• Alt 1-4 for selection of pages ( Packages, Groups, History & Pending Actions)

[timlau]

Needed shortcuts:

• [x] package filters (Updates, installed, Available & All)
• [ ] package info (descriptions, update info, filelist, requirements)
• [x] Main menu (Options, help, about, quit and docs)

[timlau]

Page for tracking current keyboard shortcuts https://github.com/timlau/yumex-dnf/wiki/Keyboard-Shortcuts-(4.3.x)

[genodeftest]

Gtk+ 3.20 introduced the GtkShortcutsWindow which could be useful here.

[genodeftest]

I've added some thoughts on the wiki page.

[timlau]

Shortcut has been reworked and GtkShortcutsWindow has been added