Reworked DatabaseConfiguration.

A template approach is now used for executing SQL operations. This
reduces code duplication.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1465754 13f79535-47bb-0310-9956-ffa450edef68
Added a new properties interface for the parameters of a DatabaseConfiguration instance.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1465755 13f79535-47bb-0310-9956-ffa450edef68