[v1] Add Env var for trader endpoint

[altafan]

Similarly to how's possible to set the tdex connect address via env var, it should be possible to set the trading one to be announced publicly in the webpage:

[altafan]

@Janaka-Steph this requires some change to the webpage. We should show the publicly accessible "Trader endpoint" view by default, and only when clicking on the Operator we ask for user and password.

At the moment, it would be impossible for a trader to see the trader endpoint because by default the webpage shows a prompt for the operator's user and password.

[Janaka-Steph]

@Janaka-Steph this requires some change to the webpage. We should show the publicly accessible "Trader endpoint" view by default, and only when clicking on the Operator we ask for user and password.

At the moment, it would be impossible for a trader to see the trader endpoint because by default the webpage shows a prompt for the operator's user and password.

Alright. I can make that change once the env var is ready.