The zone for a remote server comes from its
eureka.instance.metadataMap.zone, but we didn't (until this change)
apply the same logic to the client. If the client is registering
itslef with eureka then it will have a metadataMap itself and
we should be able to just reverse the logic.

Fixes gh-991

Makes use of StringUtils.commaDelimitedListToStringArray

Fixes gh-980

This change requires setting `ribbon.http.client.enabled=true`.

This change addresses issue #648 Getting Retry Working In RestTemplate. There is also a fix in place that addresses the issue #357 RestTemplate Error.

fixes gh-648

https://github.com/Netflix/eureka/releases/tag/v1.4.5

restores http basic auth.

Fixes gh-642

Latest Eureka from Netflix uses a different HTTP client, and it
ignores the HTTP basic credentials in a service URL. This change
partially restores the old behaviour by providing an interceptor
(ClientFilter) that has a single, global username/password
taken from the first serviceUrl that contains credentials.

Fixes gh-849

Eureka now has the option (maybe always there) to not register
and that's a sensible default in the bootstrap phase (when we
might not know the port yet).

See corresponding change in s-c-commons https://github.com/spring-cloud/spring-cloud-commons/commit/539a537abba58ed2261c4485d7f9426d2aa57453

fixes gh-643

See gh-826

Plus polish

fixes gh-836

Also does not rename another one because it fails (see gh-804). The
bug can be fixed in feign (https://github.com/Netflix/feign/pull/324),
and if that gets merged and released we can revert some of the recent
changes to the apache load balancer here.

So that it isn't instantated eagerly on startup by the RefreshScope.

Fixes gh-789

Since DiscoverClient now supports metadata natively, we can use that and not rely
on Eureka interafces at all.

Fixes gh-787. Also fixes https://github.com/spring-cloud/spring-cloud-config/issues/302

Eureka supports native placeholders, but Spring can also be used.
Added some docs to show how more explicitly.

See gh-761

fixes gh-573

fixes gh-779

Otherwise apps register the wrong health and status URLs by default. If
there is no explicit management.port we just need a default that is
the same as server.port.

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

fixes gh-579