Updated Tracker Icons

[NWBx01]

Added SlimeVR-specific tracker icons to be used and removed old icons which were unused.

I'm unfamiliar with where exactly the icons are being loaded from currently, so although I changed the paths for the tracker icons, I believe "placeholder_tracker_status.png" will still be loaded.

[Eirenliel]

Why some of the files have suffix b4bfb144?

[NWBx01]

Why some of the files have suffix b4bfb144?

I was following in the convention of icon naming as others use. The b4bfb144 portion designates that it's in the standard SteamVR blue-green gradient, whereas those without are pea green, with the exception of "tracker_status_off.png", which is a dark gray.

[Eirenliel]

I'm unfamiliar with where exactly the icons are being loaded from currently, so although I changed the paths for the tracker icons, I believe "placeholder_tracker_status.png" will still be loaded.

we should check this and fix it, otherwise this PR does nothing and can't be accepted. at the very least we need to create a separate issue to fix it. i love the icons and i want them 🥺

[ButterscotchV]

Just tested the driver build from CI, it looks like it works fine to me :3 We just need to actually disable the trackers when SlimeVR isn't connected to the driver!

[ButterscotchV]

Also just noticed that we're actually missing the icon for "not detected" (when a tracker position is disabled in SlimeVR) Here I disabled feet, you can see what the result is: