Add an KieBase Option to cache, reset and reuse disposed KieSessions

This Option can be configured using the org.kie.internal.builder.conf.SessionCacheOption class or the drools.sessionCache System property. It can have 3 values: none (default) means that there's no cache, sync means that a session is reset synchronously when it gets disposed and added to the cache, async means that this resetting process is performed asynchronously by a different thread.