Add drush command to encrypt existing data

Problem/Motivation

When adding webform encryption to existing forms with existing data, there is no way to encrypt the existing data. There's ongoing work in 📌 Create a Bulk Encryption/Decryption Service Class to facilitate encryption of pre-existing data Needs review that does not work yet. Also when viewing data that hasn't been converted, there's an existing PHP warning 🐛 PHP Warning if unserialize fails Needs work .

Steps to reproduce

Add encryption to an existing form.

Proposed resolution

Add a drush command to check and encrypt the data.