Add CameraFeed support for Windows

[0xafbf]

I started this PR based on this one: #98416

I cleaned up the structures, where original PR presented every format (width+height+framerate+encoding) as a different feed.
With this PR we create a CameraFeed per device, and each feed exposes the different formats.

Still WIP and missing some final cleanup.

[shiena]

@0xafbf
Great work! I was also working on something similar, but I've been having trouble with frequent specification changes.

Also, I'd like to request the addition of the frame_changed signal, as it seems to be missing.
https://docs.godotengine.org/en/stable/classes/class_camerafeed.html#class-camerafeed-signal-format-changed

The signal implementation seems to be missing in the macOS version, so I've submitted a PR to address this.
#104809

[AThousandShips]

If you are using someone else's work in your PR you need to give then co-author status, at least if you copy any large portions of your code from them

[AThousandShips]

Please do not bump PRs without adding additional information

[shiena]

@0xafbf
This patch should fix the build. Clarified the ambiguous fn.

diff --git a/modules/camera/camera_win.cpp b/modules/camera/camera_win.cpp
--- a/modules/camera/camera_win.cpp	(revision e777a599ed82278742eb4f8471058cf967e11b8a)
+++ b/modules/camera/camera_win.cpp	(date 1747086735202)
@@ -43,9 +43,9 @@
 #ifndef defer
 template<typename Fn>
 struct _deferClass {
-	Fn fn;
-	_deferClass(Fn&& fn): fn(fn){}
-	~_deferClass() { fn(); }
+	Fn _fn;
+	_deferClass(Fn&& fn): _fn(fn){}
+	~_deferClass() { _fn(); }
 };
 
 #define DEFER_CONCAT_INTERNAL(a, b) a##b