Update frontend workflow

[petrillek]

As a developer I need an easy to use and consistent workflow.

Implementation

• Add commands to run the gulp and gulp dev with npm.
• Update the install command to use npm ci (https://docs.npmjs.com/cli/ci.html). There were a change in npm install, which always updates both package.json and package-lock.json, which can have undersired consequences. With ci it behaves more like we are used to with composer lock files.

[petrillek]

Work in progress in branch 76-frontend-workflow.

[petrillek]

All DS components were added to packege json with semver versions so we are more able to control the flow of updates from DS.
Also added Pancake directly to package.json as there was a bug after they removed sass-versioning.
The branch has been merged to 8.x-1.x-dev – it needs to serve as base for components update.