Fix api access tokens on staging env

[rachelekm]

When starting/editing a user profile on staging the address field no longer searches destinations for a user to select. Instead, it stalls on loading (we are unable to manually type in an address to continue as well) and we cannot move on to saving the profile:

Taking a look at the network tab it appears we have no access token available for the mapbox geocoding API, so we should make that available and any other environment variables needed for the app to function on staging:

This is related to the discussion from PR #419.