[Creator] Fix wrong variable name.
[Creator][utils] Add a new file that is put utility funcitons.

From creator.py
- print_success_message()
- print_exists_message()

From checker.py
- print_container_exist_message(name)
- print_container_non_exist_message(name)
- print_container_name(name)
- print_new_line()
[Checker] Fix a function name.

is_provided_file_existence ->
is_given_file_usable
[Checker] Fix a function name.

is_provided_directory_existence ->
is_given_directory_usable
[Creator][Checker] Fix module name.

clist ->
definevalue