Removed the "print functions" from usage()
Moved set_failure_limits from miscellaneous_settings() to
user_accounts()
Moved create_ftpusers from miscellaneous_settings() to user_accounts()
Removed set_failure_limits & create_ftpusers from -u
"u") user_accounts to one line
Added a TODO
Added an echo line
Added a TODO
Clarified the all & quick harden sections in the usage
Added a section about different groups to describe their use and purpose