devhelper: Script to restart a specific webpack server
devhelper: Script to restart a specific webpack server

When tweaking webpack.config.js, it becomes necessary to restart the
webpack server. Restarting the whole web container is pretty slow for
this. This commit adds a utility script to do this quickly.

[ci skip]

akvo/akvo-rsr,akvo/akvo-rsr,akvo/akvo-rsr,akvo/akvo-rsr