Drush support for creating subthemes

[gergelypap]

Not prior, but NICE TO HAVE.

We should support fast creation of new subthemes with Drush or Drupal Console

It must:

• Create a folder with a set of files, rename files (from tietobase to tieto?)

It could:

• Ask questions from the user (Name of the subtheme, Do you want SASS or LESS, etc)