Support URLs for tsconfig files

[KnorpelSenf]

It would be cool if we could run d2n from a URL in a project that does not contain TS config yet—mostly because the project is in Deno already, which does not require such configuration files.

My suggested solution would be to test via URL if the supplied TypeScript configuration file path is a URL, and if so, to fetch the file contents from it.

[wojpawlik]

deno2node 2 CLI will allow overriding "files" to "include".

I could easily allow to specify custom fileSystem. Making tsconfig.json completely optional is likely better tho.