Add service discoveries options

[alexppg]

Is your feature request related to a problem? Please describe.
Any cool microservices framework has some kind of service discovery. Spring boot has Eureka, but it also has kubernetes.

Why would you need this? To find services to attack programmatically. For example, if k8s service discovery were implemented, you could do canary deployments and configure a service to use the unstable service based on the k8s service labels.

Describe the solution you'd like
A Service Discovery pyms service whith different backends (k8s, eureka, etc).

Describe alternatives you've considered
n/a

Additional context
Spring boot stuff.

[avara1986]

is this issue similar to #190 issue?

[alexppg]

It is, consul can be used as service discovery. This issue goes to the generic implementation and #190 to a consul backend for this implementation, in my opinion.

[Svtter]

For a cool microservices framework, the service discovery should be list at document firstly.

I spent about 20 minutes to find this chapter, it's kind of inconvenient.

[tsengia]

I would like to tack on AWS Cloud Map to the list of service discovery methods. Let me know if I should open up a separate issue for it.