(WebappPlugin) speed up service dev

Fixes #118 

I thought it made more sense to revert `reStart` to no longer depend on `npm:build` in favor of adding a new task `reStartWebapp` which runs `npm:build` and then `reStart`. This gives the developer the option to either 

1. build and run just the service with `reStart`, or
1. build and run both the service and webapp frontend with `reStartWebapp`