Add layout generation tests: Default Workflows

The goal is to add tests to:

• Scaffold all the layouts for a workflow using global variables of each possible field type.
• Scaffold all the layouts for a workflow using local variables of each possible field type.
  For all the available target platforms.

Possible field types:

• All single/multi valued basic field types.
• All single/multi valued basic subfield types (inside a complex/complexes field).