Add support for cross text resolution/conversion using Spring Cloud Netflix Eureka

[tapina]

As an alternative to the use of application properties to register URN to URL mappings, provide the ability to use a Eureka server to convert and also register when mapping annotations are scanned. This will probably require being opinionated about the format of URNs.

[nealeu]

@tapina It looks as though all could be using the service registry and discovery client abstractions as per https://docs.spring.io/spring-cloud-commons/docs/2.2.4.RELEASE/reference/html/#spring-cloud-commons-common-abstractions.