Add method writeBeanAsDraft(bean) in Binder (#11833)

Add method writeBeanAsDraft(bean) in Binder (#11833)

* Add method writeBeanAsDraft(bean) in Binder

With current Binder implementation it is not easy to support Forms, which you want to save as draft, i.e. incomplete. For example there can be big text areas, that require time to fill, or lot of fields. Therefore it is needed to that form can be saved, e.g. to other bean in incomplete state when it is not yet passing validation and this other bean can be persisted to draft storage for further editing in the future. This method helps to achieve that easily.

* Add test case for Binder.writeBeanAsDraft(bean)

Bind a field with validator, set value that does not pass validator and save, assert that value was saved.

* Updating test

* Fixing logic flaw in test

* Further improvement of the test case

* Clarification of the JavaDoc

* Fixing typo

* JavaDoc language check

* Fixing whitespace issue

* Fixing whitespaces

* Fixing whitespaces

* Updating JavaDoc