Add a github workflow to run a test with the example app.

[arrdalan]

This commit adds a workflow to test the complete functionality of the camera and the app using the example app.

1. It creates the user credentials and camera secret using config_tool.
2. It launches the server.
3. It launches the camera (TestCamera).
4. It launches the first instance of example_app that pairs directly with the camera.
5. It launches the second instance of example_app that pairs with the camera via the first example_app.
6. Both apps run for a couple of minutes and test various functionalities such as motion videos, thumbnails, livestream, and heartbeat.

[jkaczman]

Please see my comments below. Thanks!

[jkaczman]

Looks good! Thanks!