Update Spring Boot microservices to use opentracing/java-spring-jaeger

[geoand]

The easiest way to Spring Boot microservices working with Jaeger is to use the corresponding opentracing project.

If you are interested, I could take up this task

[rafabene]

Isn't the current implementation working?

[geoand]

It most certainly is.

My idea was to utilize opentracing/java-spring-jaeger to make configuration even simpler