Add support for API servers on IPv6 addresses (#48)

* Remove duplicate file for deletion

* Add support for IPv6 clusters

To correctly escape IPv6 addresses when ports are used, they must be
wrapped in square brackets [1]. This patch adds support for that,
using Ansible's ipwrap filter [2].

[1]: https://datatracker.ietf.org/doc/html/rfc4038#section-5.1
[2]: http://docs.ansible.com/ansible/latest/collections/ansible/utils/docsite/filters_ipaddr.html#wrapping-ipv6-addresses-in-brackets

* Do not abort other molecule jobs on failure

* Fix cache keys for Vagrant boxes

* Molecule: Derive overrides.yml location from scenario dir

# Conflicts:
#	molecule/default/molecule.yml
#	molecule/ipv6/molecule.yml

roles/k3s/node/templates/k3s.service.j2

@@ -7,7 +7,7 @@ After=network-online.target
 Type=notify
 ExecStartPre=-/sbin/modprobe br_netfilter
 ExecStartPre=-/sbin/modprobe overlay
-ExecStart=/usr/local/bin/k3s agent --server https://{{ apiserver_endpoint }}:6443 --token {{ hostvars[groups['master'][0]]['token'] | default(k3s_token) }} {{ extra_agent_args | default("") }}
+ExecStart=/usr/local/bin/k3s agent --server https://{{ apiserver_endpoint | ansible.utils.ipwrap }}:6443 --token {{ hostvars[groups['master'][0]]['token'] | default(k3s_token) }} {{ extra_agent_args | default("") }}
 KillMode=process
 Delegate=yes
 # Having non-zero Limit*s causes performance problems due to accounting overhead