Add support for showing the values of the parameters in foremanctl deploy --help

[shubhamsg199]

The current installer shows the values of options for foreman-installer --help
For example:

# satellite-installer --full-help | grep foreman-db-database
    --foreman-db-database                                                        Database 'production' database (e.g. foreman) (current: "foreman")
    --reset-foreman-db-database                                                  Reset db_database to the default value ("foreman")

Here the current database name is shown which is "foreman"
In the foremanctl the behaviour is different.

# foremanctl deploy --help | grep foreman-database-name
                         [--foreman-database-name FOREMAN_DATABASE_NAME]
                         [--reset-foreman-database-name]
  --foreman-database-name FOREMAN_DATABASE_NAME
  --reset-foreman-database-name

I think many customers might be using this functionality for fetching the values quickly and would be good to maintain the similarity between old and new installer

[evgeni]

I think we should talk what usecases the user might have here.

From the top of my head I can think of the following questions a user might want an answer for:

1. What are the default values for all parameters?
2. What are the currently set values for all parameters?
3. What parameters differ between the set ones and the default ones?

The puppet/kafo based installer answers 2, but is it the most important one?

Personally, I think a way to dump all variables, highlighting the ones that diverge from the default/are overriden, is an important feature, but --help is not the place for it.