Keyboard shortcut to cycle owned systems

[gendalf]

Currently you have to find your systems on the map and click on them to select, while the built-in "next system" keybinding goes through literally every jump spot, even empty space, which is pointless; this option (or an entirely new keybinding) should switch only between systems, where you already have colonies or outposts. It would make mid to late game easier.

[Nexus]

I second this.

[adrian_broher]

We (sort of) track this issue in #1028.