Provide libdom free api package

[robert3005]

What happened?

Current conjure-typescript is tied to libdom by relying on Fetch, ReadableStream and Blob. As a result it's hard to use conjure-typescript in environments that don't have DOM available, i.e. graaljs.

What did you want to happen?

We should split conjure-typescript into 2 dependencies where one of them only has necessary api bindings and the other containing implementation such that you can provide alternatives to fetch. Potentially also would require generating different api to get rid of the other two libdom references but ArrayBuffer is part of ES5 and also included in signature.