RepresentationInstances and GLB serialization

[katehryhorenko]

BACKGROUND: Multiple representations!

DESCRIPTION:

• ElementRepresentation is a base class for all representations
• GeometricElement.RepresentationInstances - collection of representation instances, where each instance contains Representation, Material and the set of representation types
• RepresentationTypes and if this representation is default is kept inside glb extensions
• GeometricElement.RepresentationInstances is ignored during serialization to json

TESTING: https://hypar.io/workflows/665b2d73-b927-461e-bed8-7e4786ca7c44

FUTURE WORK:

• Serialization to IFC
• Include Representation Instances to GeometricElement.Intersection method

REQUIRED:

• [ ] All changes are up to date in CHANGELOG.md.

COMMENTS:

• I'll be glad to discuss any of these changes

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