chore(frontend): Refactoring

Refactoring zodat de structuur van de authenticatieservice in de client duidelijker is.

frontend/src/services/auth/auth-storage.ts

@@ -0,0 +1,13 @@
+import type {Role} from "@/services/auth/auth-types.ts";
+
+export default {
+    getActiveRole(): Role | undefined {
+        return localStorage.getItem("activeRole") as Role | undefined;
+    },
+    setActiveRole(role: Role) {
+        localStorage.setItem("activeRole", role);
+    },
+    deleteActiveRole() {
+        localStorage.removeItem("activeRole");
+    }
+}