Add `rit set env` input flags option

[GuillaumeFalourd]

What is expected

Adding an explanation about how to use the rit set env input flags on the documentation.

References

Original ISSUE: ZupIT/ritchie-cli#719
Pull Request: ZupIT/ritchie-cli#923

[fernandobelettizup]

@GuillaumeFalourd I have checked current docs version and rit set env already have an explanation for input flags even with that feature not yet implemented.
What should we do in this case?

[GuillaumeFalourd]

Unnecessary