settings/production: Use webpack loader cache when not in debug mode
settings/production: Use webpack loader cache when not in debug mode

It prevents infinite reload of web application in browser when overriding
swh-web sources in docker-compose environment and modifying js sources.

SoftwareHeritage/swh-web-ui,SoftwareHeritage/swh-web-ui,SoftwareHeritage/swh-web-ui