Add a fileSize property for content resources #2358
Description
... to allow it to be captured on low / high poly count 3d models. For images height * width is a reasonable approximation of file size, but that's not possible for models (or AV). This would let a client make a more informed decision about files to load on a Choice of models. The value should be in bytes. (not a UnitValue)
eg
{
"id": "https://example.org/models/universe.glb",
"type": "Model",
"fileSize": 12437598176958151515551,
"summary": "Space is big. No really big."
}