dist/debian: Remove conflict tag for Java 11
dist/debian: Remove conflict tag for Java 11

We current require Java 8 to install the scylla-jmx package on Debian.
As Debian 10 defaults to Java 11, let's remove the conflict flag and add
Java 11 to the dependencies list.

scylladb/scylla-jmx,scylladb/scylla-jmx,scylladb/scylla-jmx