Modify the build step for front end code to remove hard-coded env variables

[sedge]

There are a couple of places in the front-end where we have configuration details (the host url for example) baked into the logic. This is gross.

The reason this is so is because the front-end doesn't have access to the server's environment variables by the time it's landed on a user's browser. The only way to get them there would be to add a templating step to the front-end build process.