Speedup database startup

[trbar]

In newer versions of EclipseLink (especially 4.x with Jakarta Persistence 3.x), the default behavior for classpath scanning has changed. When exclude-unlisted-classes is not explicitly set to true in persistence.xml, EclipseLink will:

1. Scan the entire classpath for entity classes
2. In an OSGi/Eclipse RCP environment, this means scanning ALL plugin JARs
3. This can be extremely slow when there are many plugins (as in openLCA)

https://docs.spring.io/spring-framework/reference/data-access/orm/jpa.html#orm-jpa-setup-lcemfb

Thus, we should set exclude-unlisted-classes to true in the persistence.xml

[trbar]

for testing, you can use the temp_measure_db_opening_speed branch in the olca-app, which can give profiling numbers to see the effect, for example: