[Feature] Integration with Netflix Zuul2

[kimmking]

Issue Description

Integration with Netflix Zuul2

Describe what happened (or what feature you want)

The version of Netflix Zuul2 is 2.1.3 now, Zuul2 use netty and ribon to make a non-blocking and asynchronous gateway.
Community can Integrate it.

[liangyuanpeng]

so this issue have any update?

[sczyh30]

Contributions are welcomed!

[wavesZh]

I want to try

[sczyh30]

I want to try

👍 Looking forward to your PR~ Note that Zuul 2 is asynchronous so you may need to use AsyncEntry. You could refer to the implementation of Zuul 1.x adapter.