refactor: Migrate HttpServer code to Typescript

[Ldoppea]

We will need to consume HttpServer code from Typescript code, so it is time to convert it to Typescript

This refactor has some parts that may changes the code behaviour, but I consider this should not happens:

• fix: Rethrow error on fetchAppDataForSlug
• fix: Correctly handle isRunning() as async method
• fix: Do not await getBaseFolderForFqdnAndSlug in indexGenerator
• This throw that is here to ensure correct typing but this scenario should never happen as a running server always has an URL

[zatteo]

Crazy what you found just by migrating 1 feature to ts!