Remove EOL and insecure os versions

[clintonsteiner]

jenkins/pipelines/llnode-pipeline.jenkinsfile
string(name: 'MACHINES', defaultValue: 'all', description: '''Can be "all" or a space-separated list of nodes, eg:
debian8-64 fedora22 fedora23 osx1010 ubuntu1604-64 rhel7-s390x aix61-ppc64 smartos16-64 smartos15-64 win10 win2012r2'''),
]),

Can see several out of date os's listed here.

build/ansible/inventory.yml

Line 75 in 7e5e1cb

msft-win10_vs2019-x64-1: {ip: nodejs.westeurope.cloudapp.azure.com}

Would be good to deprecate rhel7 nodes
win2012r2 servers
ubuntu1604

and any other build infrastructure which is out of date to ensure there aren't any vulnerable jenkins nodes, as well as ensuring code is being tested on the latest and greatest