Create example integration test for request with parameters

[OliverGeisel]

There should be an integration test where a request with extra parameters is performed.
For a post-request where a entity is changed the entity changes should be checked

[odrotbohm]

For reference, as discussed in lab on Tuesday, the ticket asking for support to create form submissions from instances of form-backing objects:

• Allow setting up a MockMVC form submission using an instance of the form-backing object spring-projects/spring-framework#29728