refactor: move WebSocket API to an op_crate

[lucacasonato]

Closes #8703

[bartlomieju]

Does cargo publish --dry-run pass?

[lucacasonato]

~/p/g/d/d/o/websocket ❯❯❯ cargo publish --dry-run
    Updating crates.io index
   Packaging deno_websocket v0.1.0 (/mnt/f9/Projects/github.com/denoland/deno/op_crates/websocket)
   Verifying deno_websocket v0.1.0 (/mnt/f9/Projects/github.com/denoland/deno/op_crates/websocket)
  Downloaded signal-hook-registry v1.3.0
  Downloaded itoa v0.4.7
  Downloaded thiserror-impl v1.0.23
  Downloaded anyhow v1.0.37
  Downloaded getrandom v0.1.16
  Downloaded pin-project v1.0.3
  Downloaded pin-project-internal v1.0.3
  Downloaded thiserror v1.0.23
  Downloaded syn v1.0.58
  Downloaded deno_core v0.75.0
  Downloaded 10 crates (494.5 KB) in 2.64s
   Compiling proc-macro2 v1.0.24
   Compiling unicode-xid v0.2.1
   Compiling libc v0.2.81
   Compiling syn v1.0.58
   Compiling once_cell v1.5.2
   Compiling cfg-if v0.1.10
   Compiling log v0.4.11
   Compiling memchr v2.3.4
   Compiling slab v0.4.2
   Compiling futures-core v0.3.8
   Compiling version_check v0.9.2
   Compiling typenum v1.12.0
   Compiling proc-macro-hack v0.5.19
   Compiling cc v1.0.66
   Compiling serde_derive v1.0.118
   Compiling matches v0.1.8
   Compiling serde v1.0.118
   Compiling getrandom v0.1.16
   Compiling cfg-if v1.0.0
   Compiling tinyvec_macros v0.1.0
   Compiling proc-macro-nested v0.1.6
   Compiling spin v0.5.2
   Compiling futures-sink v0.3.8
   Compiling untrusted v0.7.1
   Compiling bytes v0.5.6
   Compiling fnv v1.0.7
   Compiling itoa v0.4.7
   Compiling percent-encoding v2.1.0
   Compiling futures-io v0.3.8
   Compiling pin-utils v0.1.0
   Compiling lazy_static v1.4.0
   Compiling autocfg v1.0.1
   Compiling httparse v1.3.4
   Compiling bitflags v1.2.1
   Compiling byteorder v1.3.4
   Compiling base64 v0.12.3
   Compiling cargo_gn v0.0.15
   Compiling pin-project-internal v0.4.27
   Compiling ppv-lite86 v0.2.10
   Compiling ryu v1.0.5
   Compiling hashbrown v0.9.1
   Compiling serde_json v1.0.61
   Compiling anyhow v1.0.37
   Compiling opaque-debug v0.3.0
   Compiling pin-project-lite v0.1.11
   Compiling cpuid-bool v0.1.2
   Compiling utf-8 v0.7.5
   Compiling smallvec v1.6.0
   Compiling futures-task v0.3.8
   Compiling unicode-bidi v0.3.4
   Compiling generic-array v0.14.4
   Compiling tinyvec v1.1.0
   Compiling futures-channel v0.3.8
   Compiling form_urlencoded v1.0.0
   Compiling input_buffer v0.3.1
   Compiling http v0.2.2
   Compiling indexmap v1.6.1
   Compiling ring v0.16.19
   Compiling unicode-normalization v0.1.16
   Compiling quote v1.0.8
   Compiling iovec v0.1.4
   Compiling net2 v0.2.37
   Compiling fslock v0.1.6
   Compiling signal-hook-registry v1.3.0
   Compiling num_cpus v1.13.0
   Compiling rand_core v0.5.1
   Compiling mio v0.6.23
   Compiling idna v0.2.0
   Compiling rand_chacha v0.2.2
   Compiling rand v0.7.3
   Compiling mio-uds v0.6.8
   Compiling block-buffer v0.9.0
   Compiling digest v0.9.0
   Compiling sha-1 v0.9.2
   Compiling webpki v0.21.4
   Compiling sct v0.6.0
   Compiling rustls v0.18.1
   Compiling webpki-roots v0.19.0
   Compiling pin-project-internal v1.0.3
   Compiling thiserror-impl v1.0.23
   Compiling futures-macro v0.3.8
   Compiling tokio-macros v0.2.6
   Compiling tokio v0.2.24
   Compiling thiserror v1.0.23
   Compiling which v4.0.2
   Compiling rusty_v8 v0.15.0
   Compiling pin-project v1.0.3
   Compiling futures-util v0.3.8
   Compiling pin-project v0.4.27
   Compiling tokio-rustls v0.14.1
   Compiling url v2.2.0
   Compiling tungstenite v0.11.1
   Compiling futures-executor v0.3.8
   Compiling tokio-tungstenite v0.11.0
   Compiling futures v0.3.8
   Compiling deno_core v0.75.0
   Compiling deno_websocket v0.1.0 (/mnt/f9/Projects/github.com/denoland/deno/target/package/deno_websocket-0.1.0)
    Finished dev [unoptimized + debuginfo] target(s) in 1m 08s
   Uploading deno_websocket v0.1.0 (/mnt/f9/Projects/github.com/denoland/deno/op_crates/websocket)
warning: aborting upload due to dry run

~/p/g/d/d/cli ❯❯❯ cargo publish --dry-run
    Updating crates.io index
   Packaging deno v1.6.3 (/mnt/f9/Projects/github.com/denoland/deno/cli)
error: failed to prepare local package for uploading

Caused by:
  no matching package named `deno_websocket` found
  location searched: registry `https://github.com/rust-lang/crates.io-index`
  required by package `deno v1.6.3 (/mnt/f9/Projects/github.com/denoland/deno/cli)`

[bartlomieju]

LGTM, make sure to publish deno_websocket crate after merging this PR