Add command 'rit list formulas'

[GuillaumeFalourd]

What would you like to be added:

• A core command that allows to list available commands / formulas from a specific repository.

Why is this needed:

• When you work with various repositories, it is sometimes difficult to remember in which repository formulas are located. It could be useful to have this feature instead of looking for the formula manually.

Suggestion:

When executing the command, the user would have to inform one input inside a list with repository names.

rit list formulas
all
> commons
demo
formulas-repo

Then it would return a list of all the repository formulas with the help.json short description:

rit aws create bucket: Formula that creates an aws bucket.
rit kafka create topic: Formula that creates a topic on kafka.
...

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