Integrate follow-up date into tasklist

[zambrovski]

Tasklist API now supports follow-up dates. Integrate it into the tasklist frontend in order to show only tasks with follow-up date in the past and allow for switching this filter on/off. In addition add functionality to set the follow-up date on an individual task and show it in task details.

Copy of: holunda-io/camunda-bpm-taskpool#91