Provide Template classpath scan

**User story**
As a test designer who uses the citrus spring integration, I would like support in managing my template contexts. Template contexts are contexts which contain elements - reusable action containers.

The requested classpath scan should do the following:
- perform a scan on a pre-configured pattern and add all found contexts to the spring application container.

**Additional context**
With 'template' and 'call-template' citrus already offers templates for reusability. Also templates can be added to a spring context by specifying a named bean of type Template.

The request is thus a citrus configuration property which specifies another scan location for template contexts

Note: We already tried to add this location to @ContextConfiguration but the AnnotationConfigContextLoader is not capable to load from "locations".