Align orb-ns CLI with orb

[jsantell]

potential options (via https://github.com/subconsciousnetwork/noosphere/pull/234#issuecomment-1437392041):

• Keep It Simple: Remove key functionality from orb-ns; accept an arg or file with private key (+1 for devops currently, though extracting keys from non InsecureKeyStorage e.g. via CLI may be challenging in future key storage scenarios)
• Quick & dirty: Reimplement some subset of orb key for orb-ns
• Build out CLI ecosystem: Package orb key as orb-key, make available under both orb key and orb-ns key
• Mono CLI: Package orb-key and orb-ns under orb key and orb ns respectively, git-style (git status -> git-status) -- As ns is a dependency of orb, this has some good plus sides: a single CLI binary for users and infra, reusing mechanisms between the two; the only scenario where this is worse AFAICT is increased binary size when running bootstrap nodes outside of a gateway, which isn't a use case currently, and a workaround there is simply a "gateway" feature flag. This is my lofty preference I think.

[jsantell]

The "noun" in orb-ns commands are plural (e.g. "records") and should be singular, matching orb or git. via #276