Provide help for the project

Created a new MR with implemented hook_help().

@AstonVictor, the help() is added but it contains only a single line description. We can add uses and administration configuration details or pages.

Thanks for the suggested MR. However, the info is not complete:

• the module actually provides 3 different field formatters, two of which are "optional", meaning they only appear when their associated modules are present
• hook_help is a legacy mechanism, so any newly provided help should also be provided in the newer Help module format since https://www.drupal.org/node/3382015 → . Adjusting title accordingly.

Also, it would be good if the help actually contained some explanations about why the different formatters, how to enable and configure them, with links to the appropriate pages, etc.