Direct Sockets API: Align with WebSocketStream API.

This CL effectively refactors the idl representation of direct sockets.
Most notable changes:
* No more nesting under navigator: navigator.openTCPSocket(...) -> new TCPSocket(...)
* Member accessors are now replaced with a singleton promise socket.connection that returns all necessary info (readable/writable/local_address/peer_address)
* A member promise closed is introduced that resolves on user-initiated close and rejects on socket error
* close() by default rejects if streams are locked. Use close({force: true}) to bypass this.

Bug: 1306873
Change-Id: I9a0083837939344ca0cecb43dfc97e40009a0eb9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3528783
Reviewed-by: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Adam Rice <ricea@chromium.org>
Commit-Queue: Andrew Rayskiy <greengrape@google.com>
Cr-Commit-Position: refs/heads/main@{#986969}