Let DB properties be loaded from resource path

[alcarraz]

It would be nice that, in addition to be able to load DB properties from a file, it would be possible to load it from a resource in the class path.

I'm proposing that, similarly to the packages, use the jar: prefix for that, I'm writing the code for the PR, but if anyone else sees a reason not to do this or to do it differently I can adapt. Personally, I would prefer classpath: (or cp) or something else like that as a prefix, but for consistency I will go with jar:. Or I could implement all of them if agreed.

I'm talking about the DB_PROPERTIES system property in:

jPOS-EE/modules/dbsupport/src/main/java/org/jpos/ee/DB.java

Lines 191 to 199 in 779d1f1

	private void configureProperties(Configuration cfg) throws IOException
	{
	String propFile = System.getProperty("DB_PROPERTIES", "cfg/db.properties");
	Properties dbProps = loadProperties(propFile);
	if (dbProps != null)
	{
	cfg.addProperties(dbProps);
	}
	}