[feat]: add global story options (decorators, etc)

[itsjavi]

Description

It would be nice to be able to specify global story options from the top-level configuration.

Desired Behaviour

To be able to configure the following, from the StoryLite app:

const appOptions = {
 // ...
  storyOptions: {
        parameters: [
            // ...
        ],
        decorators: [
            // ...
        ],
        render: [
            // ...
        ],
        renderFrame: 'root', // or 'iframe',
        // ... etc
    },
}

• Parameters will be merged. If stories redefine them, they will be overriden.
• Decorators will be appended when stories define new ones. Kind of "inheritance". That's the behavior in Storybook AFAIK.
• Render and renderFrame will be overriden when redefined in stories.

Considered Alternatives

The user will have otherwise to keep a file with all common options and merge them on every story. That's a lot of boilerplate code.