[5.0] [WIP] Text.Json OpenTk.Mathematics serialization support.

[Rainboi64]

Purpose of this PR

• Adding OpenTk.Mathematics serialization support for System.Text.Json
• Will be achieved by adding the right attributes to properties and fields to the members of OpenTk.Mathematics.
• In the end this will make a seamless experience for serializing/deserializing, without anymore code needed.

Testing status

• Will be tested against randomly generated data across big sample sizes.
• Results will be compared to results by other tools and libraries.
• Will be Tested with personal projects.

Comments

• I decided to retarget this to Otk5 since it's the future of opentk and, also considering the fact that doing it with the old targets requires too much fussing and creating numerous converter classes.

[frederikja163]

This seems like a very nice addition. Cant wait to get it merged once it is done!

[NogginBops]

Is there really no way to disable serialization of properties for a specific type in Text.Json?
It's very error prone to add it manually to all properties, but if that is the only way then there is not much we can do...