chore(installation/enterprise): remove AS logos

- remove as logogs from enterprise-downloads enterprise-previous-downloads
  and installation guide
doc(rest/history): user operation log query

relates to #CAM-1757
chore(css): remove AS logo container
doc(rest/process): process diagram resource

the endpoint /process-definition/({id}|key/{key})/diagram returns the process diagram

relates to #CAM-1280
fix(welcome): revert reference to incubation img

This reverts commit 00410035fcbfa4450ae2129be35fab2253c4be6c.
fix(howto/cockpit): use jetty for dev environment
fix(event/subprocess) supports non-interrupting message event subprocess

relates to #CAM-112
fix(event/subprocess) mark non-interrupting message event subprocess

relates to #CAM-112
fix(howto/cockpit): path to webapp
feat(installation): how to configure the location of bpm-platform.xml

related to CAM-1240
chore(rest): docs new query method

HistoricVariableInstanceQuery#activityInstanceIdIn()

related to CAM-73
chore(rest): add docs about HistoricDetailQuery

related to CAM-73
fix(engine/job-executer): replace code indention with highlight blocks
feat(bpmn20/userTask): Add documentation for field followUpDate

- add docu for new user task field 'follow up date'

related to #CAM-1671
Merge branch 'master' of github.com:camunda/docs.camunda.org
feat(installation): change name of bpm-platform.xml configuration parameter

related to CAM-1240
feat(docs/bpmn20): add camunda custom extensions

* create new section for custom extensions
* add subsection for camunda extension elements
* add subsection for camunda extension attributes
* add camunda extension subsection to every BPMN element with extensions

related to #CAM-1854
chore(reset): add docs about HistoricTaskQuery

related to #CAM-1875
docs(cockpit/plugin): add instructions for client side plugin exclusion
fix(bpmn20): fix typo