Support for FINN feed parameters

[OleSan]

In the FINN spesific tests, there should be support for feed parameters. As it is now it will fail when the javascript tries to find banner.plugin and that will produce an error in the validation even if the code is correct.

The correct way to do it right now is to get a string of all the params like this:

var params = banner.plugin('contextData').parameters;

[sveisvei]

What kind of data should be exposed for test tests?

I recommend we make this integrated in the format-config.

    {
      plugins: {
         ext: ['ext-plugin-name'],
         host: ['host-plugin-name'],
         injectHostData: [{global: {}}],
         extParams: [String] or {
            key: 'value'
         }
      }
    }

[sveisvei]

Plugins must be published to npm and prefixed with gardr-. These plugins must aswell adhere to CommonJS - use a index.js file or main prop inside package.json - as scripttags will be packaged.

[sveisvei]

We will have to move format config up to validator from validator-web, but that is a-ok. Will add this within the week. @sslash should add plugins to npm as well before we can add feed-plugin setup.