Add ability to set data source directly on log/store and remove JNDI property initialization.

JDBC data sources deployed in JBoss cannot be accessed. The JBoss jndi,properties file contains something like this:

java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.factory.url.pkgs=org.jboss.naming
java.naming.provider.url=host:port

Actually, only the first and the third properties can be set using the QF/J settings. Accessing the data sources fails.

I suggest to add this and possibly other JNDI properties to JdbcUtils.getDataSource().

If just the data source is defined in the QF/J settings, a JNDI lookup is tried. In that case, all possible JNDI properties are fetched from the settings. If a property cannot be find, this will be ignored.

If there is no other JNDI property set, the default new InitialContext() without arguments is tried. It will pick up its configuration from the resource "jndi.properties" found using the class loader.

Otherwise, the configuration using direct JDBC driver and URL etc. is used.