TOT-97 "fix error 502"

Issue: The problem here is actually that systemd was killing the apps due to timing out because the service type was set to notify .

Fix:

1. used Type=simple and configure the service file
2. splitted into 2 services. one for the backend and one for the frontend
3. serve both modules in production profile, not in dev profile as before
   1. for the frontend, add build as a step to serve it as a static site (and changed from npm run dev to npm run start)
   2. for the backend, changed from npm run dev to npm start

Closes TOT-97