Upgrade jena to 3.8.0

[gutee]

Change Jena version to 3.8.0 because of two security issues:

• First issue was the dependency with xerces (https://nvd.nist.gov/vuln/detail/CVE-2013-4002), and the dependency is removed in the upgrade.
• Second issue is with jackson dependency (Jackson Deserializer security vulnerability via default typing (CVE-2017-7525) FasterXML/jackson-databind#1599) which is updated to 2.9.5 and if default types are not used, it's not a security issue.

[HolgerKnublauch]

This is hopefully OK. I say hopefully because we have internally not yet updated to 3.8 in the TopBraid copy of this so I am less confident that everything works as it should. Moving forward, please do not rely on any 3.8 specific changes as I cannot accept PRs until we are up to date too.