Implement adjustments for Java 11

[TobiasNx]

Also updating metafacture to 11

[TobiasNx]

@fsteeg hier auch @acka47 als functional reviewer?

[TobiasNx]

I am not sure about this. Java 11 did not compile because it reported the following:

method javax.xml.stream.XMLEventFactory.createStartElement(javax.ml.namespace.QName,java.util.Iterator<? extends javax.xml.stream.events.Attribute>,java.util.Iterator<? extends javax.xml.stream.events.Namespace>) is not applicable

refering to line 165 with the change in 151 it worked.

[fsteeg]

That code is originally from lobid-gnd (there, it works with Java 11 in your PR?), and is not actually used for rppd. I think all the Convert* classes could be removed.

[TobiasNx]

I tried to remove the Convert* classes: f0bae2f

The result runs into errors. Maybe you could have a look @fsteeg in spare time. Not super urgent.

[fsteeg]

It doesn't seem like the removal is the problem. IndexAppTest is failing, getting 0 hits.

I think the point to start investigating is why it worked in lobid-gnd, but not here. Should be the same, since this is a fork of lobid-gnd. I think you should look into the details of what you did there and here, and try to do it the same way.

(I'm also currently not getting either this or lobid-gnd to properly run in VS code, with module-related errors)