Use protocol buffers instead of JSON

[buijs-dev]

Implement protocol buffers instead of JSON (de) serialisation to improve performance.

Solution:

• Add property to ksp block to optin for protobuf.
• Use kotlinx proto generator to generate a proto schema for each @Response annotated class.
• Generate dart code by using the proto schema.
• Change generated widgets to use the generated protobuf classes (instead of the from/to JSON).
• Add encoding/decoding wrapper (just like the decode/encode in flutter-engine-kmp) to read/write bytes.