--properties should not require someone to write JSON on the command

[larsks]

The help for the --properties option to openstack esi lease create says:

  --properties PROPERTIES
                        Record arbitrary key/value resource property information. Pass in as a json object.

...but I am using the CLI because I don't want to interact with the API using JSON. It would be much kinder to the user to permit a "key=value" syntax, e.g.:

openstack esi lease create -p weight=100 -p color=red ...

And perhaps offer a --properties-json option for the rare case that someone actually wants to write JSON on the command line.