Update Readme of https://github.com/camunda/camunda-bpm-examples/tree/master/cockpit/cockpit-fullstack-count-processes to contain no dead links.

It currently contains the dead link https://github.com/camunda/camunda-bpm-examples/tree/master/cockpit/cockpit-fullstack-count-processes#how-client-side-plugins-work

Acceptance Criteria (Required on creation):

• links to client side development are working