Support hosting static pages

[anbraten]

Lagoss currently requires a function index file to be configured. Static projects wont have such a file by default and only contain static .html files and assets.

Possible options

• Add a default index.js entryfile serving the index.html as needed.
• Remove the need for an entryfile and implement routing into the serverless component

[anbraten]

A script like this seems to allow basic static hosting:

export function handler(request: Request) {
    return new Response('', {
      status: 302,
      headers: {
        location: '/404.html',
      },
    });
}