Create hasItenWhich and itsdeclination for maps

[Riduidel]

Currently, CollectionFieldInformer and MapFieldInformer``both have predicate on direct value containment (containingfor Collection,`containingKey`and`containingValue` for Map).
These query predicates are "nice" for literal values, but of little interest for managed values.
it would be far better to have Informer chaining in Collection/Map.
This could be achieved by adding the following predficates

public class MapFieldInformer<KeyType, ValueType>
        extends ObjectFieldInformer {
    public FieldInformerType hasKeyWhich();
    public FieldInformerType hasValueWhich();
}

and

public class CollectionFieldInformer<ValueType> extends ObjectFieldInformer {
    public FieldInformerType hasItemWhich();
}

Implementation should be able to return the most meaningfull Informer, based upon keys and values known types.

The main interest is that it could allow dynamic informers to benefit from these implementation, creating methods such as (for our beloved gaedo-test-beans)

public class DynamicUserService extends DynamicFinder<User, UserInformer> {
    public Iterable<User> findAllByPostsHasItemWhichNoteEqualsTo(long note);
}

quite engrish, no ?