Add annotation for merging method name and class name in action name

[programmerr47]

We need to add annotation that will allow to combine interface name and method name to one action name. For example:

interface Sample {
    @DesiredAnnotation fun action()
}

will give category = sample and action = sampleaction

Also, need to think about splitters. For example, to generate action = sample-action or action = sample_action

Suggested names for annotation are: @short, @Prefix, @WithPrefix, @HasPrefix
Suggested parameters:
name - specify prefix name (default is name of class in lower case)
splitter - specify splitter string (default is nothing)

Suggested behavior:

• can be used on interface and method
• class annotation gives behavior to all methods of this interface
• if we have annotation on interface and same annotation on method, then method annotation wins

[programmerr47]

Need to add doc for new annotation @HasPrefix

[programmerr47]

Added: https://github.com/programmerr47/ganalytics/wiki/Annotations#hasprefix