Add authentication interfaces for login and registration

src/interfaces/auth.ts

@@ -0,0 +1,19 @@
+export interface ILogin {
+  email: string;
+  password: string;
+}
+
+export interface ILoginResponse {
+  token: string;
+}
+
+export interface IRegister {
+  first_name: string;
+  last_name: string;
+  email: string;
+  password: string;
+}
+
+export interface IRegisterResponse {
+  user_id: string;
+}