Lets user have full control over how the Observable is created with
sane defaults for eager/non-eager cases.

- The fix adds a necessary buffer between the rx-rs adapter and
the timeout operator introduced in AbstractCommand. Unfortunately,
the hystrix operator does not comply with RS backpressure requirements.
It will always request an unbounded demand to a source regardless of
the command consumer demand. With this commit we protect RS adapter and
downstream flow from overflow. Ideally a rework of the operator should
be planned.

- The eureka instance auto registration also changes the secure port when the server port is random (0)

Fixes gh-2303

Update documentation to reflect https://github.com/spring-cloud/spring-cloud-netflix/issues/1048

* Add new Zuul filters endpoint and refactor routes endpoint
* Refactor FiltersEndpoint
- Extend from AbstractEndpoint and simplify code
- Move tests classes into package endpoint
- Remove usage of Lombok
* Conditionally enable Zuul routes and filters endpoints
* Provide FilterRegistry to FiltersEndpoint via constructor

fixes gh-2386

Extract separate class TurbineClustersProvider to be able to provide custom solution for retrieving configured clusters (#2219)

Otherwise there would be an explosion of overloaded methods.

# Conflicts:
#	spring-cloud-netflix-hystrix-stream/src/test/java/org/springframework/cloud/netflix/hystrix/stream/HystrixStreamTests.java
#	spring-cloud-netflix-zuul/src/main/java/org/springframework/cloud/netflix/zuul/ZuulProxyAutoConfiguration.java

See https://github.com/spring-cloud/spring-cloud-commons/issues/265

Updates to 2.0.0

# Conflicts:
#	spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/metrics/DefaultMetricsTagProvider.java
#	spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/DeferredResultSubscriber.java
#	spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/ResponseBodyEmitterSubscriber.java
#	spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/RxResponse.java
#	spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/ribbon/support/RibbonCommandContextTest.java
#	spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/ObservableReturnValueHandlerTests.java
#	spring-cloud-netflix-dependencies/pom.xml

see https://github.com/Netflix/archaius/pull/522