Modernize the Drush commands

Updated variable name as requested, hence moving in NR.

Rebased and added to 🌱 Planned for 1.21 version release Active .

Reviewed changes, looks good to me. Hence, RTBC.
Note: Core Version requirement has been updated and Drupal Core 8 support is dropped. Probably this requires a new minor release.

Resolved conflict and rebased.