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

### 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: https://github.com/adobe/aem-project-archetype/commit/7dbfbf625aab601cf8d2dba0fec31e39fb9fefc6

Start in the ui.frontend module's npm configuration and inspect the watch command, using the cited commit as context for the regression. Verify that npm run watch installs npm-run-all and invokes webpack for a newly generated Archetype 41 project; completion is confirmed when the command runs without the reported executable error and webpack watches successfully.

Written by the indexing model from the issue text.