Adds several skybox scenes to addon

addons/AllSkyFree/Demo/AllSky_DemoEnvironment.fbx.import

@@ -0,0 +1,37 @@
+[remap]
+
+importer="scene"
+importer_version=1
+type="PackedScene"
+uid="uid://ctu1saig8pk0h"
+valid=false
+
+[deps]
+
+source_file="res://addons/AllSkyFree/Demo/AllSky_DemoEnvironment.fbx"
+
+[params]
+
+nodes/root_type="Spatial"
+nodes/root_name="Scene Root"
+nodes/apply_root_scale=true
+nodes/root_scale=1.0
+nodes/import_as_skeleton_bones=false
+nodes/use_node_type_suffixes=true
+meshes/ensure_tangents=true
+meshes/generate_lods=true
+meshes/create_shadow_meshes=true
+meshes/light_baking=0
+meshes/lightmap_texel_size=0.1
+meshes/force_disable_compression=false
+skins/use_named_skins=true
+animation/import=true
+animation/fps=15
+animation/trimming=true
+animation/remove_immutable_tracks=true
+animation/import_rest_as_RESET=false
+import_script/path=""
+_subresources={}
+fbx/importer=1
+fbx/allow_geometry_helper_nodes=false
+fbx/embedded_image_handling=1