Implement objects_input for templates

[kdp-cloud]

For better maintainability in the future, app/views/sample_types/_form.html.erb should be refactored to use objects_input.js or the objects_input helper.

https://github.com/seek4science/seek/blob/56a6f0f6b7106ccc6b924b339d2239983b3e8573/app/views/templates/_form.html.erb#L104-L110