Added more parameters to JDBCDataStorefactory to handle idle connections

These are the new parameters introduced in JDBCDataStorefactory in this pull request in order to handle idle connections issues:

**TEST_WHILE_IDLE** = If IDLE connections should be validated before using them
**TIME_BETWEEN_EVICTOR_RUNS** = Idle object evictor periodicity
**MIN_EVICTABLE_TIME** = Min time for a connection to be idle in order to be evicted
**EVICTOR_TESTS_PER_RUN** = Number of connections checked during a single evictor run