Add another HTTP server to make manual testing easier.
Add another HTTP server to make manual testing easier.

I was using it for a unit test but decided it wasn't actually useful for
that, but it still may be useful for other purposes.

Signed-off-by: Patrick Vacek <a38520cbbe2e974bc8b7ea86877dd3c7115ca2d7@gmail.com>

advancedtelematic/aktualizr,advancedtelematic/sota_client_cpp,advancedtelematic/aktualizr,advancedtelematic/sota_client_cpp,advancedtelematic/aktualizr,advancedtelematic/aktualizr