Add support for listing available catalogs and projects

[markpollack]

A centrally controlled list of catalogs and project can be browsed after installation of the CLI. The location to look for these lists can be customized, but there are default values to get users started with the CLI.

The current command names would introduce too much overlap, project catalog add and project add are confusing. Restructure to the following

Catalog project Commands
       catalog project add: Add a project catalog
       catalog project list available: List project catalogs that are available to add
       catalog project list installed: List locally installed project catalogs
       catalog project remove: Remove a project catalog

Project Commands
       project add: Add a project
       project list: List projects available to use
       project remove: Remove project

Catalog Command Commands
       catalog command add: Add a command catalog
       catalog command list available: List command catalogs that are available to add
       catalog command list installed: List locally installed command catalogs
       catalog command remove: Remove a command catalog

Command Commands
       command add: Add a user-defined command
       command remove: Delete a user-defined command
       command new: Create a new user-defined command