Adding verbose and minor improvements
     Attending the bug reported #20
     Linter the full sheet code
     Add feature to check the user that want to use, it is for add a security layer in order to avoid use OS users
     For give extra compatibility when use with web site parts, now if exist the web user group, the new ftp user will be append to this group
     Sorting some actions in order to improvement the uses case logic
     Fix the documentation/code for the uses case, when want to use a custom certificate and private key