* Cleaning up the documentation folder
This change cleans up the documentation folder in the CLI repo. The
changes are the following:
* Delete old content that is invalid moving forward.
* Move cli-installation-scenarios to the `specs` sub-folder.
* Add a sub-folder for documentation that deals with working with the repo
* Add a general sub-folder
* Finally, change the README.md to reflect this.
Also, this change adds a document that covers CLI UX guidelines for
authors of new commands.
* Firt round of PR feedback changes
