DRILL-7467: Jdbc plugin enhancements and fixes
1. Added logic to close data source when plugin is closed.
2. Added disabled jdbc plugin template to the bootstrap storage plugins.
3. Added new jdbc storage plugin configuration property sourceParameters which would allow setting data source parameters described in BasicDataSource Configuration Parameters.
4. Upgraded commons-dbcp2 version and added it to the dependency management section in common pom.xml.
closes #1956
