This patch adds the basic files and only one test now.
Consecutive patches will add more test cases.
Change-Id: Iebc28e9781357c11a664c6b0d203a4c20a63a6ca
Although zun's commands are simpler.
But for users, auto-complete function is still more convenient.
Change-Id: Id7b64f72a84db62fd6fa006f98c3e705f8cca095
Implements: blueprint zun-autocomplete-commands