Create an initial web service

Create a maven project structure.

One mock webservice should be included. Both Json and XML payload accepted.
Configuration of this webservice (response body, response headers, http status code) should be fully configured in a configuration file.

Invoication details (headers, payload) should be logged.

Closes #T124

.travis.yml

@@ -0,0 +1,4 @@
+sudo: required
+services: docker
+script:
+  - docker-compose up -d --build