Feature/81 slash command support (#192)

* Update discord.js

* Migrate to slash commands

* Clean up imports

* Update permissions

* Fix guild-specific commands not showing up

* Fix changes requested

src/constants/CommandResponse.ts

@@ -1,7 +0,0 @@
-export enum CommandResponse {
-    Ok,
-    Unauthorised,
-    ServerNotSetup,
-    NotInServer,
-    FeatureDisabled,
-}

src/constants/EmbedColours.ts

@@ -0,0 +1,3 @@
+export default class EmbedColours {
+    public static readonly Ok = 0x3050ba;
+}

src/constants/ErrorMessages.ts

@@ -1,27 +0,0 @@
-import { CommandResponse } from "./CommandResponse";
-
-export default class ErrorMessages {
-    public static readonly InsufficientBotPermissions = "Unable to do this action, am I missing permissions?";
-    public static readonly ChannelNotFound = "Unable to find channel";
-    public static readonly RoleNotFound = "Unable to find role";
-
-    public static readonly UserUnauthorised = "You are not authorised to use this command";
-    public static readonly ServerNotSetup = "This server hasn't been setup yet, please run the setup command";
-    public static readonly NotInServer = "This command requires to be ran inside of a server";
-    public static readonly FeatureDisabled = "This feature is currently disabled by a server moderator";
-
-    public static GetErrorMessage(response: CommandResponse): string {
-        switch (response) {
-            case CommandResponse.Unauthorised:
-                return this.UserUnauthorised;
-            case CommandResponse.ServerNotSetup:
-                return this.ServerNotSetup;
-            case CommandResponse.NotInServer:
-                return this.NotInServer;
-            case CommandResponse.FeatureDisabled:
-                return this.FeatureDisabled;
-            default:
-                return "";
-        }
-    }
-}