This change creates the ability to run a server separate from the
console web server to serve the front end app. You can run it with
`satellite run ui`. Since there are now potentially two servers instead
of one, the UI server has the option to act as a reverse proxy to the
api server for local development by setting `--console.address` to the
console backend address and `--console.backend-reverse-proxy` to the
console backend's http url. Also, a feature flag has been implemented
on the api server to retain the ability to serve the front end app. It
is toggled with `--console.frontend-enable`.
github issue: https://github.com/storj/storj/issues/5843
Change-Id: I0d30451a20636e3184110dbe28c8a2a8a9505804
