test(load): add machine jwt profile test for a single user (#8593)

# How the Problems Are Solved

Adds a new load test to use the token endpoint with a single user by
multiple threads.

load-test/src/use_cases/machine_jwt_profile_grant_single_user.ts

@@ -0,0 +1,35 @@
+import { loginByUsernamePassword } from '../login_ui';
+import { createOrg, removeOrg } from '../org';
+import {createMachine, User, addMachineKey} from '../user';
+import {JWTProfileRequest, token, userinfo} from '../oidc';
+import { Config } from '../config';
+import encoding from 'k6/encoding';
+
+const publicKey = encoding.b64encode(open('../.keys/key.pem.pub'));
+
+export async function setup() {
+  const tokens = loginByUsernamePassword(Config.admin as User);
+  console.info('setup: admin signed in');
+  
+  const org = await createOrg(tokens.accessToken!);
+  console.info(`setup: org (${org.organizationId}) created`);
+  
+  const machine = await createMachine(`zitachine`, org, tokens.accessToken!);
+  console.info(`setup: machine ${machine.userId} created`);
+  const key = await addMachineKey(machine.userId, org, tokens.accessToken!, publicKey);
+  console.info(`setup: key ${key.keyId} added`);
+
+  return { tokens, machine: {userId: machine.userId, keyId: key.keyId}, org };
+}
+
+export default function (data: any) {
+  token(new JWTProfileRequest(data.machine.userId, data.machine.keyId))
+  .then((token) => {
+    userinfo(token.accessToken!)
+  })
+}
+
+export function teardown(data: any) {
+  removeOrg(data.org, data.tokens.accessToken);
+  console.info('teardown: org removed');
+}