[nostory] refactor boost cli tool, improve its documentation

Context:

in walking @chrobid through using the boost cli tool, we realized that:

• its documentation could use some improvement
• some of the help commands were outdated
• command invocation could be more intuitive

Changes:

ergo, this MR:

• refactor cli commands to use snake-case instead camel_case (as most bash commands observe this pattern)
• use create-<newthing> instead of new-<newthing> (to maintain consistency with REST verbs)
• add docs about how to list numbers/channels (and generally add a bit more context to the boost section)
• remove help messages about non-existent commands, and make existing messages reflect current app state