Timer job never unlocked after an exception

**Describe the bug**
please refer to https://github.com/flowable/flowable-engine/issues/2354

**Expected behavior**
I think there's still a possibility to have a lock, now UnlockTimerJobsCmd is run in the catch code block, but there is no chance to execute this code block when the app process is closed by exception.

**Additional context**
Need a thread "ResetExpiredTimerJobsRunnable" run on an independent Thread just like ResetExpiredJobsRunnable, the lock happens in any exception will be unlocked.

Empieza leyendo el issue enlazado 2354 y comparando ResetExpiredTimerJobsRunnable con el ResetExpiredJobsRunnable existente y el UnlockTimerJobsCmd mencionado aquí. Se considera terminado cuando los bloqueos de los timer jobs se restablecen incluso si el proceso de la aplicación se cierra durante una excepción, sin depender del bloque catch.

Escrito por el modelo de indexación a partir del texto del issue.