stream: make readable & writable computed

This makes readable and writable automatically computed based on the stream state.

Effectivly deprecating/discouraging manual management of this.

Makes the properties more consistent and easier to reason about.

Refs: https://github.com/nodejs/node/issues/29377

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines