Add how to deal with dependencies in scenarios

[yossisp]

Add Integration Test Scenarios of Event-Driven Modules section to the docs to describe how to write tests when modules don't directly depend on other modules (that is not via Spring dependency injection mechanisms).

1. Add a use case for usage of @ApplicationModuleTest(extraIncludes = "")
2. Add a use case for usage of @SpringBootTest + @EnableScenarios.