Support passing in JSON parameter (value) data from a file.

Note: this new feature would pre-req. supporting the JSON data type first.

Although the flag "param-file" is an invocation concept:
```
$ wsk action invoke --result hello --param-file parameters.json
```
We need to consider allowing a JSON file (under the package would be used to set the values (or default values) for an individual parameter when its type is JSON.

This feature SHOULD support the same ability (i.e., import of data) for future data types as well. For example, another data schema which would define parameter data (perhaps in XML).