Add user_guild_settings support (#1365)

* user guild settings

* Use direct collection

* I'm a goof

* double goof

* Structure properties

* Forgot to register listener

* wrong class names

* No more get in docs

* avoid waterfalls, bot checks

* trycatch

wow i thought i already did this :notlikecat:

* 👀

* Update ClientUser.js

* Update ClientUserGuildSettings.js

* Update UserGuildSettingsUpdate.js

* Update ClientUserChannelOverride.js

* Update ClientUserGuildSettings.js

src/structures/ClientUserGuildSettings.js

@@ -0,0 +1,47 @@
+const Constants = require('../util/Constants');
+const Collection = require('../util/Collection');
+const ClientUserChannelOverride = require('./ClientUserChannelOverride');
+
+/**
+ * A wrapper around the ClientUser's guild settings.
+ */
+class ClientUserGuildSettings {
+  constructor(data, guild) {
+    this.guild = guild;
+    this.channelOverrides = new Collection();
+    this.patch(data);
+  }
+
+  /**
+   * Patch the data contained in this class with new partial data.
+   * @param {Object} data Data to patch this with
+   */
+  patch(data) {
+    for (const key of Object.keys(Constants.UserGuildSettingsMap)) {
+      const value = Constants.UserGuildSettingsMap[key];
+      if (!data.hasOwnProperty(key)) continue;
+      if (key === 'channel_overrides') {
+        for (const channel of data[key]) {
+          this.channelOverrides.set(channel.channel_id,
+            new ClientUserChannelOverride(this.guild.client.user, channel));
+        }
+      } else if (typeof value === 'function') {
+        this[value.name] = value(data[key]);
+      } else {
+        this[value] = data[key];
+      }
+    }
+  }
+
+  /**
+   * Update a specific property of the guild settings.
+   * @param {string} name Name of property
+   * @param {value} value Value to patch
+   * @returns {Promise<Object>}
+   */
+  update(name, value) {
+    return this.guild.client.api.guilds(this.guild.id).settings.patch({ data: { [name]: value } });
+  }
+}
+
+module.exports = ClientUserGuildSettings;