Add drush script to convert crop image effects to focal point in bulk

Problem/Motivation

When you have a lot of image styles and with crop effects and want to change them to focal point you need to do a lot of manual work.

Proposed resolution

Add a Drush script to convert all the crop image effects to focal point.

I've added a custom command to convert all the crop effects.
'drush convert-scale-and-crop' or short 'drush csac'.