feat(kex): introduce kex for 8.0+, used for alpine and fedora 30+

[kostasns]

This PR is a second part of dev-sec/ansible-ssh-hardening#281
It also addresses #144 somewhat

From Fedora 30 ( the one which is currently used in rndmh3ro/docker-fedora-ansible:latest image for testing ) OpenSSH 8.0p1 is installed. And with changes in dev-sec/ansible-ssh-hardening#254 a separate list of kex was introduced for 8.0 and above in ansible role.

So this PR modifies the test to check for correct list of kex for Fedora with version 30 and higher. I've also took the liberty to set the kex80 for alpine, although currently not used in testing docker-alpine-ansible image will fall into same OpenSSH 8.0+ category.

This potentially will break other tests
It seems chef-ssh-hardening repo does set kex66 list for both Fedora 29 and 30
don't know if there are other places to watch out for
What is the best way forward for this one ?

[kostasns]

Not being to familiar with Ruby, can someone advise on how to fix the remaining errors ? Thanks :)

[chris-rock]

Thank you @kostasns for raising awareness with this pull request. Your PR pushed the community. We went with #172 instead of this one since it covered more operating systems and turned green on CI. I am going to close this PR.

[kostasns]

No problem at all. Glad to help :)