Include npm-run-all as dev dependency in ui.frontend module and run webpack in watch command

[brunob15]

Expected Behaviour

The npm run watch command should work on Archetype 41.

Actual Behaviour

The npm run watch command does not work on Archetype 41 as the npm-run-all package is not installed as a dependency and the command never runs webpack.

Reproduce Scenario (including but not limited to)

Brand new projects created with Archetype 41

Steps to Reproduce

Create new AEM project with Archetype 41, navigate to the ui.frontend module and run npm run watch.
Error 'npm-run-all' is not recognized as an internal or external command, operable program or batch file shows up.

Sample Code that illustrates the problem

Commit where it was introduced: 7dbfbf6