fixes gh-2298

* Move Archaius to its own module.  

Fixes gh-2300\

fixes gh-2309i

These things are now much better dealt with in Spring MVC and WebFlux

Fix issue gh-1054

This move should be transparant to users of spring-cloud-starter-eureka.

fixes gh-579

* For Java 8 users, Spectator is the recommended metrics library as Servo is now deprecated in favor of Spectator
* Servo support now needs to be specifically enabled via @EnableServo, even if servo-core is included on the classpath
* Added starter modules for both Spectator and Atlas support
* ServoMetricReader defines a convention for mapping tag-based metrics to hiearchical names for rendering by the Actuator /metrics endpoint

Via spring 4.2 new AsyncHandlerMethodReturnValueHandler

fixes gh-231

This was kind of ugly, and caused a static usage of the eureka
DiscoveryCLient to become necessary again, just so the @Bean that is
provided for the user stays accurate (it has to be the one in the main
application context, even if the parent boot strap has different
instance metadata).

I tested with a vanilla Eureka server and config server, and used the
client in tests/eureka-first.

Fixes gh-268

Replaces the boolean flag (loadbalance) for switching between service
resolution (by name) or straight URL bashing.

removed classes now in spring-cloud-commons

If the prefix is set we also set configPath=<prefix> in the
instance metadata, so config clients can pick it up and add it
to the home page URL.

Fixes gh-64, fixes gh-65

See gh-42

Add support for Ribbon loadbalancing in RestTemplate via an HttpRequestInterceptor that when supplied a uri such as http://myservice/my/endpoint (where myservice is a service as defined in a service registry, such as Eureka), it replaces 'myservice' with the actual host and port as returned from the configured ribbon loadbalancer.

closes gh-12

Without extracting to autoconfig the @ConditionalOnMissingBean won't
always work because it is dependent on the order of the configuration
classes being processed (and autoconfig always somes last).