With this commit you can specify either a URL or a serviceId for the
Turbine server location.
Note that `spring.boot.admin.turbin.url` is replaced by
`spring.boot.admin.turbine.location`.

closes #373

With this change it is possible to include credentials in the instance
metadata which will then be used to access the client endpoints using
HTTP Basic authorization.

closes #359

With this commit the support for Turbine is completly revised. From now
on Turbine is supported via a separate module and is integrated as top
level view.

closes #306

By using the netflix/hystrix-dashboard this module allows you to view the
metrics from hystrix/turbine in the spring boot admin server. This module needs
to be added explicitly.

closes #147

As now with spring boot 1.4 there is a special goal for generating the build-
information, we use it for displaying the version in spring boot admin. The old
info.version property still works but is deprecated. From now on
build.info.version is taken into account.

fixes #205