This PR aims to organize a little the files within `infrastructure_files` folder and adds some new ENV vars to the process.
1. It creates the `artifacts` folder within the `infrastructure_files` folder, the idea behind it is to split templates from artifacts created after running `./configure.sh`. It makes it easier to cp/rsync only `artifacts` content to the final server/destination.
2. Creates `NETBIRD_TURN_DOMAIN` and `TURN_DOMAIN` ENV vars. The idea behind it is to make it possible to split the management/signal server from TURN server. If `NETBIRD_TURN_DOMAIN` is not set, then, `TURN_DOMAIN` will be set as `NETBIRD_DOMAIN`.
3. Creates `*_TAG` ENVs for each component. The idea behind it is to give the users the choice to use `latest` tag as default or tie it to specific versions of each component in the stack.
Diego Noguês