Output not only Enabled:false from --auto-gen-config.

All the Max parameters and some EnforcedStyle parameters can now
be generated into rubocop-todo.yml. More can be added later.

These parameters are generated instead of Enabled:false, making the
available configuration options more visible.
Use generated rubocop-todo.yml from .rubocop.yml.
Merge pull request #693 from jonas054/improve_rubocop_todo

Improve rubocop todo