Research feasibility of using yapapi as part of goth

[kmazurek]

The goal here is to determine whether it would be beneficial to include yapapi as a dependency of goth. Ideally, it would be possible to choose whether a given test should use yapapi or the lower-level, built-in yagna API client included in goth.

Potential gains:

• enabling test assertions based on yapapi events (see also: [EVENTS] list places where current event interface is important yapapi#773)
• simpler setup for complex test scenarios (using the built-in client proves to be tedious and requires re-using helper methods, see goth tests in yagna)
• ya-aioclient compatibility

Potential risks:

• more complexity and support overhead in goth
• tighter coupling between the projects
• issues with circular dependencies, as yapapi uses goth for its integration tests