title: Symfony 4 several forms (steps) for one entity
body: <p>I have table and entity class with multiple (30) fields. I want to build no one big form, but for example 3 forms (10 fields each), that will save following fields in the same record in the table.
  This is simple to do in pure PHP or other simpler framework where I do it manually. How to do this in Symfony, where many things are more automated? 
  I look for a general tip, which approach to use.</p>