Run scheduled E2E tests

[wojcik91]

• make the e2e pass again (failing after adding setup wizard)
• run e2e tests on schedule (once a night)
• use predefined combinations of proxy & core images (main + main, dev + dev, 1.5.1 + 1.5.2 etc)
• find a better way (that anyone will actually care about) to notify people on failure
  • maybe put e2e status in uptime kuma?