Serializing "editable" flag

If there is no form on request, the editable is set to false automatically.
Editable on publish request is set to false, even if there is a form.

What's Changed

• Krist/editable field default value by @SilvyPuzzlewell in #71
• editable is false for publish draft request type by @SilvyPuzzlewell in #72
• bug fix by @SilvyPuzzlewell in #73

Full Changelog: 2.2.1...2.2.2