cli: add feature to cache docstrings for an api
cli: add feature to cache docstrings for an api

cached verb dictionary stores the following as a list:
- name of the API
- params (list of args)
- docstring

Signed-off-by: Rohit Yadav <0fa72ca37c4b5fa62675187ce32ea6c9f842fd52@apache.org>

remibergsma/cloudstack-cloudmonkey,Interoute/cloudmonkey-interoute,apache/cloudstack-cloudmonkey,apache/cloudstack-cloudmonkey,remibergsma/cloudstack-cloudmonkey,Interoute/cloudmonkey-interoute