Add channel cloning

Changes:
    - Added function cloneChannel
    - Modified createChannel to support cloneChannel
   - Added clone(reason) method on channel structure
    - Added channel cloning tests

src/helpers/channels/clone_channel.ts

@@ -0,0 +1,28 @@
+import { cacheHandlers } from "../../cache.ts";
+import { createChannel } from "./create_channel.ts";
+import { CreateGuildChannel } from "../../types/guilds/create_guild_channel.ts";
+import { DiscordenoChannel } from "../../structures/channel.ts";
+
+/** Create a copy of a channel */
+export async function cloneChannel(channelId: string, reason?: string) {
+  const channelToClone: DiscordenoChannel | undefined = await cacheHandlers.get(
+    "channels",
+    channelId
+  );
+  //Return undefined if channel is not cached (unsure about error handling)
+  if (!channelToClone) return;
+
+  //If "name" is null or undefined as specified by types
+  channelToClone.name ??= "new-channel";
+
+  //Merge channel data with reason for createChannel options
+  const creationData = {
+    reason,
+    ...channelToClone,
+  };
+  //Create the channel (also handles permissions)
+  return createChannel(
+    channelToClone.guildId!,
+    creationData as CreateGuildChannel
+  );
+}