[#33] Ckeditor4 LTS integration

Check list to complete before assigning a MR to someone:

• Link related issues on Related Issues;
• Update documentation;
• Comment relevant changes, why/what lead us to make this change;
• Review at least once you own MR;
• Tests green;

Related issues:

• #33 (closed) (Integrate CKEditor 4 LTS)
• drupalsite-operator#100 (closed) (Update the Operator to pass the secret for ckeditor4lts as an environmental variable)