Upgrade to DataNucleus 4

Second attempt at upgrading to DataNucleus 4. In contrast to the previous patch,
this patch fixes a compatibility issue in AuthorizationRecord when upgrading
from an earlier version of dCache using postgresql.

Target: trunk
Require-notes: no
Require-book: no
Move to Java 8

Require Java 8 for compilation and for execution.

A few code changes were required due to changes in how generics are
treated in Java 8.

Once commited, I expect somebody needs to take care of Jenkins.

Target: trunk
Require-notes: yes
Require-book: yes
Upgrade to LiquiBase 3.2.1

The bug we suffered in 3.2.0 is claimed to be fixed.

Target: trunk
Require-notes: no
Require-book: no