Add auth server, login page, users table, create user script, etc

inventory-server/auth/schema.sql

@@ -0,0 +1,6 @@
+CREATE TABLE `users` (
+  `id` INT AUTO_INCREMENT PRIMARY KEY,
+  `username` VARCHAR(255) NOT NULL UNIQUE,
+  `password` VARCHAR(255) NOT NULL,
+  `created_at` TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+);