Add OutputFormat to IAM report

[nimrodkor]

Allow outputting the IAM report as a json file.

Resolves #637

[0xdabbad00]

I think you may have missed committing a file, as I believe all this does is provide a command-line argument that outputs a file with either a .html or .json extension, meaning it's the same file, just with different extensions, so the .json file would be an HTML file.

[nimrodkor]

@0xdabbad00 The other thing is it skips the template.render(t=t) command - so it actually dumps the json into a file, instead of creating an HTML file out of it and then saving it to a file

[0xdabbad00]

Ah, ok. So I guess the use case is so you can feed this data into your own template somehow.