Rework `AbstractResourceType::getProperties` approach

[dresslerdemos]

Currently the getProperties method must return a list of PropertyBuilder instances. The has disadvantages:

• The name of the property is stored inside the PropertyBuilder instance, which allows to return multiple instances for the same property name. The behavior when such thing is done is undefined.
• When implementing the getProperties method it is not clear what effect the order of the list has.
• Inside the getProperties implementation the methods createAttribute, createToOneRelationship and createToManyRelationship can be used to easily create and configure properties. However, in case the instance needs to be adjusted further down the logic it needs to be saved into a variable. With many properties this becomes hard to manage. A better approach would be if the properties were available via properties or getters in a corresponding class. This class could be the resource type itself, utilizing property-read magic, a separate class generated from annotations in the resource type class or the entity class or something different.
• The PropertyBuilder class seems too generic. There should be at least separate classes for attributes and relationships. Relationships may be differentiated into to-many and to-one relationship classes. Another feature may be to return a different interface after a setter was used, so that previously used setters are not suggested for further calls. This can be archived by automatically generating the interfaces. When this is explored further one needs to consider that this feature may be confusing during usage and may even hinder code writing in cases where the instance needs to be saved into a variable to call an already used setter again later, depending on some conditions.

[dresslerdemos]

Beside

Another feature may be to return a different interface after a setter was used, so that previously used setters are not suggested for further calls.

which was scrapped, the ideas laid out above have been implemented.