Fix editor suffixes and degrees conversion

* Functions to convert to/from degrees are all gone. Conversion is done by the editor.
* Use PROPERTY_HINT_ANGLE instead of PROPERTY_HINT_RANGE to edit radian angles in degrees.
* Added possibility to add suffixes to range properties, use "min,max[,step][,suffix:<something>]" example "0,100,1,suffix:m"
* In general, can add suffixes for EditorSpinSlider
Not covered by this PR, will have to be addressed by future ones:

* Ability to switch radians/degrees in the inspector for angle properties (if actually wanted).
* Animations previously made will most likely break, need to add a way to make old ones compatible.
* Only added a "px" suffix to 2D position and a "m" one to 3D position, someone needs to go through the rest of the engine and add all remaining suffixes.
* Likely also need to track down usage of EditorSpinSlider outside properties to add suffixes to it too.

scene/scene_string_names.cpp

@@ -143,7 +143,7 @@ SceneStringNames::SceneStringNames() {
 	v_offset = StaticCString::create("v_offset");
 
 	transform_pos = StaticCString::create("position");
-	transform_rot = StaticCString::create("rotation_degrees");
+	transform_rot = StaticCString::create("rotation");
 	transform_scale = StaticCString::create("scale");
 
 	_update_remote = StaticCString::create("_update_remote");