[exploration] support async solid defs in appropriate python versions

should we support asyncio.run ing solids ?

@solid(...)
async def fancy():
  x = await do_stuff()
  return x

should we support async generators in python 3.6+ ?

@solid(...)
async def fancy():
  x = await do_stuff()
  yield Output(x)

should we have an in process engine that gathers over multiple async solids ?

[JBrVJxsc]

AWESOME!!! THANK YOU!!!

[yuhan]

closing as @solid can now decorate async def functions since 0.11.4. will track work about the proper executor support in a separate issue https://github.com/dagster-io/dagster/issues/4041