feat(ui): add keybinding for target radial

[mwerle]

Add a keybinding to open the target radial menu. The bind is empty by default as per the other target radials.

This allows keyboard controls to fly to, orbit, or dock with the current frame object or nav target, as appropriate.

[sturnclaw]

Looks simple enough - I have only one spot where I'd prefer some cleanup be done to increase the future maintainability of the code.

I cannot promise a timeline, but I'll be working on allowing Lua to register inputs without the need for the C++-side AddActionBinding calls.

[mwerle]

I cannot promise a timeline, but I'll be working on allowing Lua to register inputs without the need for the C++-side AddActionBinding calls.

It appears the timeline was <12hrs... should I update this PR to make use of the new API?

[sturnclaw]

It appears the timeline was <12hrs... should I update this PR to make use of the new API?

The only thing that's currently missing to do so is a nice place to hang a Lua-side InputFrame off of - we don't currently have a good way to track when the WorldView is made active and push/pop an InputFrame in response. Some work would likely be needed to amend PiGuiView.cpp to trigger LuaEvent::Queue("onViewActive", GetViewName()); etc. in the OnSwitchTo and OnSwitchFrom methods.

I leave it at your discretion whether you want to merge this first, then convert all of the radial menu keybinds as described, or expand the scope of this PR and tackle all of the above in this PR.

[mwerle]

I leave it at your discretion whether you want to merge this first, then convert all of the radial menu keybinds as described, or expand the scope of this PR and tackle all of the above in this PR.

Let's keep the scope to the actual feature for now; please merge if acceptable and I'll create a TODO ticket to put in the relevant plumbing and upgrade all radial menus / Lua keybinds in a clean-up ticket.

[sturnclaw]

Merged, thanks!