Use a back-end to access openapi base url

[randycylonix]

It is probably not a good idea to embed the openapi API key directly in the client app.
A securer way is to allow config to include a proxy/back-end URL where the API key will be inserted and send to openapi.

1. App sends request to the back-end server. 
2. Back-end server forwards the request to openapi with the api key stored only in the back-end and wait for the response inline.
3. Back-end server receives the response from openapi.
4. Back-end server sends the response back to the client app.
5. App receives the response from the back-end server finishing the request.