Replaced Responsible/Coach for Manager collection

This makes the relationship more general and generic
Composite component for person selection

Component allows to select person from a list and add it to a
collection. From this collection, one can remove the element afterwards.
removed unneccessary generic parameters

From Java 7 onwards type parameters are not needed when instantiating an
object whose type is already known.
Modified relation between Person and Team

All associations between these entities are of the same type now, but
are enriched by a role setting (e.g. player and manager), which makes
the relation extendible.