Implement OpenXR Foveated rendering support

modules/openxr/doc_classes/OpenXRInterface.xml

@@ -77,6 +77,13 @@
 				Returns [code]true[/code] if the given action set is active.
 			</description>
 		</method>
+		<method name="is_foveation_supported" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if OpenXRs foveation extension is supported, the interface must be initialised before this returns a valid value.
+				[b]Note:[/b] This feature is only available on the compatibility renderer and currently only available on some stand alone headsets. For Vulkan set [member Viewport.vrs_mode] to [code]VRS_XR[/code] on desktop.
+			</description>
+		</method>
 		<method name="set_action_set_active">
 			<return type="void" />
 			<param index="0" name="name" type="String" />
@@ -98,6 +105,12 @@
 		<member name="display_refresh_rate" type="float" setter="set_display_refresh_rate" getter="get_display_refresh_rate" default="0.0">
 			The display refresh rate for the current HMD. Only functional if this feature is supported by the OpenXR runtime and after the interface has been initialized.
 		</member>
+		<member name="foveation_dynamic" type="bool" setter="set_foveation_dynamic" getter="get_foveation_dynamic" default="false">
+			Enable dynamic foveation adjustment, the interface must be initialised before this is accessible. If enabled foveation will automatically adjusted between low and [member foveation_level].
+		</member>
+		<member name="foveation_level" type="int" setter="set_foveation_level" getter="get_foveation_level" default="0">
+			Set foveation level from 0 (off) to 3 (high), the interface must be initialised before this is accessible.
+		</member>
 		<member name="render_target_size_multiplier" type="float" setter="set_render_target_size_multiplier" getter="get_render_target_size_multiplier" default="1.0">
 			The render size multiplier for the current HMD. Must be set before the interface has been initialized.
 		</member>