Split 3D editor sensitivity freelook sensitivity into its own setting

This allows configuring orbit sensitivity and freelook sensitivity
independently from each other. Often, it's needed to use a lower
freelook sensitivity compared to the orbit sensitivity.

Also, when using a FOV scale lower than the default
(using Alt + mouse wheel), the mouse sensitivity is now scaled
to make it easier to use freelook to look at distant objects.
This does not affect orbiting and panning.

editor/editor_settings.cpp

@@ -574,6 +574,8 @@ void EditorSettings::_load_defaults(Ref<ConfigFile> p_extra_config) {
 	// 3D: Freelook
 	_initial_set("editors/3d/freelook/freelook_navigation_scheme", false);
 	hints["editors/3d/freelook/freelook_navigation_scheme"] = PropertyInfo(Variant::INT, "editors/3d/freelook/freelook_navigation_scheme", PROPERTY_HINT_ENUM, "Default,Partially Axis-Locked (id Tech),Fully Axis-Locked (Minecraft)");
+	_initial_set("editors/3d/freelook/freelook_sensitivity", 0.25);
+	hints["editors/3d/freelook/freelook_sensitivity"] = PropertyInfo(Variant::REAL, "editors/3d/freelook/freelook_sensitivity", PROPERTY_HINT_RANGE, "0.01, 2, 0.001");
 	_initial_set("editors/3d/freelook/freelook_inertia", 0.0);
 	hints["editors/3d/freelook/freelook_inertia"] = PropertyInfo(Variant::REAL, "editors/3d/freelook/freelook_inertia", PROPERTY_HINT_RANGE, "0, 1, 0.001");
 	_initial_set("editors/3d/freelook/freelook_base_speed", 5.0);

editor/plugins/spatial_editor_plugin.cpp

@@ -2253,7 +2253,8 @@ void SpatialEditorViewport::_nav_look(Ref<InputEventWithModifiers> p_event, cons
 		_menu_option(VIEW_PERSPECTIVE);
 	}
 
-	const real_t degrees_per_pixel = EditorSettings::get_singleton()->get("editors/3d/navigation_feel/orbit_sensitivity");
+	// Scale mouse sensitivity with camera FOV scale when zoomed in to make it easier to point at things.
+	const real_t degrees_per_pixel = real_t(EditorSettings::get_singleton()->get("editors/3d/freelook/freelook_sensitivity")) * MIN(1.0, cursor.fov_scale);
 	const real_t radians_per_pixel = Math::deg2rad(degrees_per_pixel);
 	const bool invert_y_axis = EditorSettings::get_singleton()->get("editors/3d/navigation/invert_y_axis");