Coroutines based database-vertx implementation

[DmitrySadchikov]

The implementation of the database-vertx module, which is based on Kotlin's coroutines, instead of reactor classes. Kora context is saved and obtained exclusively through CoroutineContext.

Bug fixes:

• In Context.Kotlin.inject method, kora context injection was added to CoroutineContext. Because of this bug, Context.Kotlin.current method always returned a new empty context.