Updated contexts and proxy so spring data links are correct when run thr...

...ough zuul proxy.

customers :9000/api/customers
stores :8081/api/stores
ui :9900/
ui proxy :9900/api/*

@dsyer @joshlong What do you think?  It's not ideal, but we could put /api in [config-repo/application.yml](https://github.com/spring-cloud-samples/config-repo/blob/master/application.yml) so we don't repeat it.