fix(user-guide): fix type in table of content

siganvio is now signavio

Closes: #CAM-1058
chore(rest): change permission type docs
Merge branch 'master' of github.com:camunda/docs.camunda.org
feat(user guide): migrate and extend job executor docs

- transactions in processes
- job acquisition
- job execution
- concurrent execution
- exclusive jobs
- multiple engine setups
- cluster setups
- job execution in heterogeneous clusters

related to CAM-49
Merge branch 'master' of github.com:camunda/docs.camunda.org
chore(user-guide): add sources for job executor drawings
fix(user-guide): rename image file to be displayed correctly
feat(jboss): custom process engine configuration
feat(auth): add authorization to docs

related to #CAM-1023