[FEATURE] Provide CLI help option

[arnaud-m]

Is your feature request related to a problem? Please describe.

At this time, the help message is displayed if there is no arguments or invalid arguments. This is no general description of the command, only a description of the options.

• Related to #122

Describe the solution you'd like

• Provide short and long help messages.
  • Display the short message in the two bases above.
  • Display the long message if the option is given.
• Write a description of each command

Provide usage examples

CMD  ## short
CMD -h ## long
CMD --help ## long

[arnaud-m]

• GNU Coding Standard