Gh56 xmi serializer

[antoineatstariongroup]

Prerequisites

• I have written a descriptive pull-request title
• I have verified that there are no overlapping pull-requests open
• I have verified that I am following the SysML2.NET code style guidelines
• I have provided test coverage for my change (where applicable)

Description

Fix #56

• XMI Serializer via CodeGen
• Created a validation test that assert that the Quantities.sysml can be deserialized and serialized again with the same content.

Note, for the validation test, some adjustement had to be done :

• Align XMI namespace
• discard some value
  • (%20 replaced by space, ignoring encoding and ignoring some explicit default value that are sometimes present)