src: sharding cleanup and checkReady rewrite (#3393)

* src: Step 1 of who knows how many

* src: Remove accidentally committed test file

* src: Remove useless added property in package.json

* docs: Trailing spaces, come back >.>

* src: Buhbye uws, we will miss you..not!

* src: Move 'auto' shard selection from totalShardCount to shards

* src: tweak

* src: Filter out floats from shard IDs
You want half of a shard or what?

* src: Misc cleanup and bugfix for GUILD_BAN_ADD

* src: Rewrite checkReady

* src: Misse this while merging master into my branch

* typings: Bring these up to date

* typings: Forgot allReady event

* src: Don't checkReady if the shard isn't waiting for guilds

* src: Fix a possible bug for when the ws dies and the session becomes -1

* src: Hopefully fix last edge case that could case a shard to infinitely boot loop

* src: Rename totalShardCount to shardCount

* src: Small bugfix

* src: Correct error message for shardCount being imvalid

Co-Authored-By: bdistin <bdistin@gmail.com>

* src: Small tweaks

* src: If this doesn't fix the issues I'm gonna throw a brick at my PC

* src: I swear, STOP BREAKING

* src: *groans at a certain snake*

* src: Use undefined instead of null on destroy in close event

Setting it to null sets the close code to null, which causes a WebSocket error to be thrown. The error is thrown from WebSocket, although there is no connection alive. Fun times!

* src: @SpaceEEC's requested changes

* src: Remove zucc from discord.js

Discord is removing support for it, sooo... Bye bye

* src: Missed this

* src: Apply @kyranet's suggestions

Co-Authored-By: Antonio Román <kyradiscord@gmail.com>

* src: @kyranet's suggestions

* src: Remove pako, update debug messages
- Pako is officially gone from both enviroments
  Install zlib-sync on node.js if you want it
- Improve a few debug messages some more
- Discover that internal sharding works in browsers but please don't do that

.eslintrc.json

@@ -1,7 +1,7 @@
 {
   "extends": "eslint:recommended",
   "parserOptions": {
-    "ecmaVersion": 2018
+    "ecmaVersion": 2019
   },
   "env": {
     "es6": true,