Add support for positional arguments

[gautamomento]

e.g.
momento cache create --name mycache can be also done as momento cache create mycache

Similarly for Gets and Sets
moment cache set --key myKey --value myValue can also be done as momento cache set myKey myValue
moment cache get --key myKey can also be done as momento cache get myKey

[kvcache]

My only regret is that I have but 1 thumbsup to give from this account

[danielamiao]

I helped contribute another thumb