DATACMNS-534 - Add reading / writing property information to PersistentProperty.

We introduced `@ReadOnlyProperty` which can be used for excluding properties from being persisted. The `AnnotationBasedPersistentProperty.isReadOnly()` will return `true` in that case, while `PersistentProperty.shallBePersisted()` returns `false`.

`@Transient` supersedes `@ReadOnlyProperty`.

`@ReadOnlyProperty` can be used as meta-annotation for others like `@TextScore` in spring data mongodb.