Support for testWhileIdle, timeBetweenEvictionRunsMillis and minEvictableIdleTimeMillis parameters

Tomcat connection pool (and dbcp) has possibility to test connections while idle, instead of onBorrow/onReturn but parameters needed to fine tune this feature were not read from application.properties.
This pull request adds support for testWhileIdle, timeBetweenEvictionRunsMillis and minEvictableTimeMillis respecting the differences in default values between DBCP and Tomcat Connection Pool.