Separated schema reading and codec models in module 'Schema' to make it reusable IR-996

[rkharisov]

Description of the Change

Iroha2 have similar with Fearless scheme with metadescription of API models consumed and sent by peer. We decided to separate common for both projects logic to allow reuse it for Iroha2 Android SDK

• Moved common code to new gradle module 'scheme'
• Removed 'RuntimeSnapshot' parameter from 'encode' and 'decode' methods of 'Type' due it specific for substrate blockchai. It causes late initiation of properties of 'RuntimeSnapshot'

Benefits

• Reusing code

Possible Drawbacks

• Harder to make changes without breaking code in one of the projects