feat: remove datastores and implement Managers (#3696)

* Initial commit: add 5 initial managers

- Base manager
- GuildChannelManager
- MessageManager
- PresenceManager
- Reaction Manager
- Added LimitedCollection

* Add GuildEmojiManager, various fixes

* Modify some managers and add guildmembermanager

* Initial integration

* Delete old stores

* Integration part two, removed LRUCollection

- Most of the integration has been finished
- TODO typings
- Removed LRUCollection, needless sweeping

* Typings + stuff i somehow missed in ChannelManager

* LimitedCollection typings/ final changes

* Various jsdoc and syntactical fixes, Removed Util.mixin()

* tslint fix

* Grammatical and logical changes

* Delete temporary file placed by mistake

* Grammatical changes

* Add missing type

* Update jsdoc examples

* fix: ChannelManager#remove should call cache#delete not cache#remove

* fix recursive require

* Fix missed cache in util

* fix: more missed cache

* Remove accidental _fetchMany change from #3645

* fix: use .cache.delete() over .remove()

* fix: missing cache in ReactionCollector

* fix: missed cache in client

* fix: members is a collection not a manager

Co-Authored-By: Sugden <28943913+NotSugden@users.noreply.github.com>

* fix: various docs and cache fixes

* fix: missed cache

* fix: missing _roles

* Final testing and debugging

* LimitedCollection: return the Collection instead of undefined on .set

* Add cache to BaseManager in typings

* Commit fixes i forgot to stage yesterday

* Update invite events

* Account for new commit

* fix: MessageReactionRemoveAll should call .cache.clear()

* fix: add .cache at various places, correct return type

* docs: remove mentions of 'store'

* Add extra documented properties to typings

Co-authored-by: Sugden <28943913+NotSugden@users.noreply.github.com>
Co-authored-by: SpaceEEC <spaceeec@yahoo.com>

src/managers/VoiceStateManager.js

@@ -0,0 +1,37 @@
+'use strict';
+
+const BaseManager = require('./BaseManager');
+const VoiceState = require('../structures/VoiceState');
+
+/**
+ * Manages API methods for VoiceStates and stores their cache.
+ * @extends {BaseManager}
+ */
+class VoiceStateManager extends BaseManager {
+  constructor(guild, iterable) {
+    super(guild.client, iterable, VoiceState);
+    /**
+     * The guild this manager belongs to
+     * @type {Guild}
+     */
+    this.guild = guild;
+  }
+
+  /**
+   * The cache of this manager
+   * @property {Collection<Snowflake, VoiceState>} cache
+   * @memberof VoiceStateManager
+   * @instance
+   */
+
+  add(data, cache = true) {
+    const existing = this.cache.get(data.user_id);
+    if (existing) return existing._patch(data);
+
+    const entry = new VoiceState(this.guild, data);
+    if (cache) this.cache.set(data.user_id, entry);
+    return entry;
+  }
+}
+
+module.exports = VoiceStateManager;