Install correct version of openjdk on Debian

[r4fek]

On Debian 10 (current stable) openjdk-8 isn't available, openjdk-11 should be installed instead.

[tarzanek]

@r4fek I like this change, but it means our support matrix will cut out old Debian/Ubuntus
care to fix also
https://github.com/scylladb/scylla-ansible-roles/blob/master/ansible-scylla-node/meta/main.yml#L15
and others?
(so we restrict the Debians and Ubuntus to supported ones? Also will this work on Debian 9? )

The support should ideally be at least for 9 and 10
same for Ubuntu, I guess 16.04 should get unsupported too (since it's standard support ended in April 2021)

[tarzanek]

Per molecule Ubuntu 18, 20 work
care to enable molecule for Debian 9 and 10? (that would be a proof your code just works (tm) )

[tarzanek]

Sample how to enable molecule: 7c47452
I am pretty sure you can borrow configs from Ubuntu 18