PhantomCamera Debug UI

[ramokz]

Problem

In the Editor, it can be tricky to know which PhantomCamera is active, what priority it has, what the second-highest priority is etc. without selecting various PhantomCameras in the hierarchy.

The proposal is to have a togglable debug UI that will show relevant information when actively working with the plugin.

Proposed Solution

Add a debug UI that enables will show the following. Should be attached to the PhantomCameraHost:

• Active PhantomCamera's name
• Active PhantomCamera's priority
• Second-highest priority int value

Note: Priority for visual noise is key. It needs to be easily accessible, but simultaneously show enough to remain useful.
This can be expanded upon should more feature become relevant to this.

[ramokz]

Decided to not continue with this work as there's too much overlap between this and #33. The existence of the latter makes it hard to justify the former.