Add custom default values support in templates

[joffrey-bion]

Currently, template generation uses property inspection for any non-primitive and non-enum type.
This leads, for instance, to inspection of java.util.Date objects, which results in #42.

We should allow for custom default values for any given class, and special cases of primitive wrapper classes and enum classes should just be pre-configured.
Maybe we should consider pre-configuring Date objects as well.

[ST-DDT]

Maybe this could be implemed as/extended with an annotation as well. The annotation could provide example values for fields (e.x. name) like John Doe. This would also work on class level. Every time a field with that class is encountered the given example value.

@interface ApiExample {

    String value();

    ValueType type() default ValueType.TEXT/Integer/Float;

}

[joffrey-bion]

Very good suggestion. I don't have time to work on this right now, but I wanted to rework the templates anyway at some point, so I'll keep that in mind.

[joffrey-bion]

Specific issue opened for dates: #45