Deprecate encoding of images using IFC (IfcPixelTexture)

I don't think that it is a role for IFC to encode images in a list of hexBinary digits. Is this used?

```
ENTITY IfcPixelTexture
SUBTYPE OF (IfcSurfaceTexture);
Width : IfcInteger;
Height : IfcInteger;
ColourComponents : IfcInteger;
Pixel : LIST [1:?] OF IfcBinary;
```

It leads to this: [https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/annex/annex-e/tessellation-with-pixel-texture.ifc](https://standards.buildingsmart.org/IFC/RELEASE/IFC4/ADD2_TC1/HTML/annex/annex-e/tessellation-with-pixel-texture.ifc)

```
#57= IFCPIXELTEXTURE(.T.,.T.,'TEXTURE',#58,$,256,256,4,("0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000","0FF000000", ...
```

This looks quite similar in XML and JSON. Any Graph-oriented scheme (RDF, LPG), this should not result in a List of hexBinary elements in any case (which it is in the OWL version of IFC); yet it should be stringified - or link to be made to a binary file (JPEG).

I suggest finding a means to reference a JPEG file or similar, which has such encoding embedded.