Rework JSON Serialization mechanism for Data Model

[Danielku15]

Issues

Fixes #461

Proposed changes

This PR reworks the internal JSON serialization mechanism for the data model. Instead of having the manually maintained serializer, we reuse the JSON serializer from the settings. Changes consist of

• Replace manually maintained copyTo and cloning system
• Replace manual Score JSON serialization with auto-generated one
• Include and Extend TS Clone and JSON Transformers for C# generation

Checklist

• I consent that this change becomes part of alphaTab under it's current or any future open source license
• Changes are implemented
• Existing builds tests pass
• New tests were added
• Write code docs
• Performance tests and improvements (also build chain)
• Double check old json vs. new json to avoid missing details

Further details

• This is a breaking change
• This change will require update of the documentation/website