BS-7731, thread were not stopped because of we never closed hibernate session factory

Conflicts:
	bpm/bonita-core/bonita-process-engine/src/main/java/org/bonitasoft/engine/api/impl/PlatformAPIImpl.java
BS-7731, do not throw exception when a work did not succeed because of the thredpool that is shutdown, log a warn

Conflicts:
	bpm/bonita-home/common/server/platform/conf/services/cfg-bonita-work-factory.xml
	services/bonita-services-test-conf/src/test/resources/conf/cfg-bonita-work-impl.xml
	services/bonita-work/bonita-work-impl/src/main/java/org/bonitasoft/engine/work/DefaultBonitaExecutorServiceFactory.java
	services/bonita-work/bonita-work-impl/src/test/java/org/bonitasoft/engine/work/DefaultBonitaExecutorServiceFactoryTest.java