feat: use list to display virtools encodings settings, instead of raw string.

- use list to show bmap encoding settings, instead of user input raw string. it will give a more obvisous interface.
	* add bmap encoding setting properties in ptrprop_resolver.
	* update ptrprop_resolver for more clear usage.
- following features has not been implemented yet.
	* default value for bmap encoding list.
	* the bridge function in ioport_shared module (filter empty item in result)
	* validate encoding list result when importing and exporting virtools file.

bbp_ng/OP_UV_rail_uv.py

@@ -19,7 +19,7 @@ class BBP_OT_rail_uv(bpy.types.Operator):
 
     def execute(self, context):
         # check material
-        mtl: bpy.types.Material = PROP_ptrprop_resolver.get_rail_uv_material()
+        mtl: bpy.types.Material = PROP_ptrprop_resolver.PtrPropResolver.get_rail_uv_material()
         if mtl is None:
             UTIL_functions.message_box(
                 ("No specific material", ), 
@@ -34,7 +34,7 @@ class BBP_OT_rail_uv(bpy.types.Operator):
 
     def draw(self, context):
         layout: bpy.types.UILayout = self.layout
-        PROP_ptrprop_resolver.draw_rail_uv_material(layout)
+        PROP_ptrprop_resolver.PtrPropResolver.draw_rail_uv_material(layout)
 
 #region Real Worker Functions