fix(README): remove commons-ui from auto-build enabled

The camunda-commons-ui repository is only aimed
to provide libraries or utilities for the other UI aspects
of the webapps, it does not have to be build.

Related to: 
https://groups.google.com/d/msg/camunda-bpm-dev/Ctmc3sQSfxc/xkTrM1tWQ4EJ
fix(demoData): serialize potential approvers as JSON
Merge branch 'master' of github.com:camunda/camunda-bpm-webapp
chore(npm): use camunda nexus to proxy npm registry

related to #CAM-2971
chore(example): provide a further process with task without a name