feat(api): initial implementation of the auth system (#30)

Adds the auth system but does not add all required features. They will be handled in other tickets

server/types/express.d.ts

@@ -0,0 +1,21 @@
+/* eslint-disable @typescript-eslint/no-unused-vars */
+import type { NextFunction, Request, Response } from 'express';
+import type { User } from '../entity/User';
+
+declare global {
+  namespace Express {
+    export interface Session {
+      userId?: number;
+    }
+
+    export interface Request {
+      user?: User;
+    }
+  }
+}
+
+export type Middleware = <ParamsDictionary, any, any>(
+  req: Request,
+  res: Response,
+  next: NextFunction
+) => Promise<void | NextFunction> | void | NextFunction;