Add more safeguards - esp. the low-hanging fruit

[shreyb]

@LTrestka set up this nice SafeguardDCS class, to which we've added only one method - createUser. We should think of other safeguards (like deleteUser?), and add them, especially if they're low-hanging fruit we know we shouldn't allow this CLI to run.

@LTrestka , @cathulhu - does this sound like a good next-meeting topic?

[shreyb]

We can get more of these from the ferry task list (maybe Lisa has it).

APIs to not run:

• deleteUser
• More to come

Another idea:

• Have middle ground where tool asks for verification (Y/N)
• Then next step would be adding SNOW API call to verify that a ticket was filed to do the action requested, and it called this API, but failed
• Final version would make this functionality a plugin, of which the SNOW API call would be an example implementation