async/await support

I guess we need to modify these lines:

• https://github.com/dry-python/returns/blob/master/returns/functions.py#L34
• https://github.com/dry-python/returns/blob/master/returns/functions.py#L49

And add await there. And it should be working. I am also not sure about types and .bind methods that expects callables. Will it work with asyncio?

[sobolevn]

Partial support is introduced since 0.6.0

[proofit404]

In my opinion, we should implement the first option and postpone awaitable results to the moment in the future when someone will come with a meaningful real-world example of its usage.

To support pipeline and safe decorators we should

• Check if a decorated function is a coroutine. With the inspect module for example.
• In this case, wrapper function defined by decorator should be a coroutine as well with single await in it.