Add a api job to clean up cache and temp tables on a periodic basis

This will allow sites to cleanup the cache and temp tables more deterministically rather than the current probabilistic method. Also add optional parameters so we can also clear the DB cache and memory caches if needed

In future releases we should also add other generic stuff to this job. things i can think of include:

• Clean up old import files
• Rotate, archive and compress old CiviCRM.*.log files