feat(jobexecutor): merge fox platform jobexecutor

- merge old fox platform jobexecutor to fit into new bpm platform
  architecture

  * expose Java SE Thread Pool Executor through JMX on Tomcat
  * expose Job Executor settings (lock time, lock owner, wait time ...)
    through JMX on Tomcat & Glassfish
  * move support for dispatching to multiple process engines to
    JobExecutor core
  * merge ejb-service module with ejb-jobexecutor-service module
  * add ExecutorService to RuntimeContainerDelegate

- make ProcessEngineConfiguration class configuratble on JBoss AS 7
  through subsystem.xml (management model)

- plug custom Job Retry Strategy
Merge branch 'master' of github.com:camunda/camunda-bpm-platform