CTL+Blockfrost [Metatask]

[klntsky]

The implementation of our Blockfrost backend will partially cover Blockfrost API. We only need some of the endpoints (a complete spec can be downloaded here)

The roadmap:

1. Make Contract runtime and ConfigParams parametrize-able with a backend. Move every query layer function to a handle (as in handle pattern) Make Contract query backend configurable  #1119
2. Implement a stub for Blockfrost handle, with all methods throwing "unimplemented". Implement query stubs for blockfrost backend handle. #1120
3. Proceed with implementing Blockfrost queries based on OpenAPI spec Implement Blockfrost queries based on OpenAPI spec [Metatask] #1365 (Q: can we generate the client code? A: not unless we want to write a custom generator)
4. Add blockfrost to runtime Wrap blockfrost as a runtime service #1358
5. Add blockfrost to devShell: Introduce blockfrost to devShell #1359

Testing:

• Add ability to run tests with Blockfrost to the template #1421
• Add a generic test runner for Blockfrost-based tests #1420

Some technical details can be found in #524