Drupal Coding Standards

[codechefmarc]

Summary

This PR fixes/implements the following bugs/features

• Checked the code against phpcs with the Drupal standard and refactored the following
• Added dependency injection to the SubThemeCommands for 3 services
• Moved SubThemeGenerator to a service
• Cleaned up unused use statements

Explain the motivation for making this change. What existing problem does the pull request solve?

Prepares the module for Drupal.org and best coding practices.

Documentation update (required)

No changes to documentation, command works exactly the same way as before.

How to review this pull request

• Pull down this repo into the /web/modules/contrib directory and switch to this branch
• Pull down the emulsify_drupal repo into the /web/themes/contrib directory and switch to the release-base-theme branch.
• Enable the Emulsify Tools module - drush en emulsify_tools
• Run the command drush emulsify my_awesome_theme
• Verify that a new sub theme is generated in /web/themes/custom/my_awesome_theme

[callinmullaney]