Move the backend connection to ENV

To make things more convenient and to prevent code change whenever we want to change the backend, we need the backend connection to be part of the ENV of the frontend.

Start by locating where the frontend's backend connection is defined and how environment configuration is currently loaded. Move that connection setting into the frontend environment configuration, then verify that changing the environment value changes the backend target without a source-code edit.

Written by the indexing model from the issue text.