Browser support

[rojvv]

We need to support browsers. For this, we might want to keep away from std/node as much as we can, since it has many Deno-only code, and we have already faced enough problems with it.

• Reduce bundle size to work. (Done in refactor: remove database sessions #19.)
• Stop depending on std/node/crypto.ts. (Done in refactor: replace crypto from node compat with already existing subtle implementations #20.)
• Stop depending on std/node/fs.ts. (Done in refactor: replace std/node/fs.ts dependencies with native Deno APIs #23.)
• Stop depending on std/node/net.ts. (Done in fix: load /std/node/net.ts dynamically and skip it in browsers #24/fix: #24 follow up #25.)
• Replace w3cwebsocket with the already-implemented WebSocket. (Done in refactor: replace w3cwebsocket with WebSocket #26.)

[rojvv]

Our current problem is in generating the auth key. It is stuck here:

grm/src/network/mtproto_plain_sender.ts

Line 31 in 87751eb

body = await this._connection.recv();