Idempotent ansible role for Keepalived service

# Config examples
<details>
  <summary>Using template config</summary>

    keepalived_config:
      global_defs:
        router_id: t1-dev-rabbitmq
      vrrp_track_process:
        haproxy:
          process: haproxy
          quorum: 1
          delay: 2
      vrrp_instance:
        VRRP_1:
          state: MASTER
          virtual_router_id: 50
          priority: "{{ ansible_default_ipv4.address.split('.')[-1][-2:] }}"
          interface: "{{ ansible_default_ipv4.interface }}"
          unicast_src_ip: "{{ ansible_default_ipv4.address }}"
          unicast_peer:
            - 10.89.10.71
            - 10.89.10.72
            - 10.89.10.73
          virtual_ipaddress:
            - "10.89.10.112/32 dev {{ ansible_default_ipv4.interface }}"
          track_process: 
            - haproxy

</details>

<details>
  <summary>Complete config override</summary>

    keepalived_config_override: |
      global_defs {
        router_id {{ patroni_cluster_name | default('default') }}
      }
      vrrp_track_process haproxy {
        process haproxy
        quorum 1
        delay 2
      }
      vrrp_instance VRRP_1 {
        state MASTER
        virtual_router_id {{ keepalived_vip.split('.')[-1][-3:] }}
        priority {{ ansible_enp3s0.ipv4.address.split('.')[-1][-3:] | default(ansible_default_ipv4.address.split('.')[-1][-3:]) }}
        interface {{ ansible_enp3s0.device | default(ansible_default_ipv4.interface) }}
        unicast_src_ip {{ ansible_enp3s0.ipv4.address | default(ansible_default_ipv4.address) }}
        unicast_peer {
      {% for peer in groups.all %}
          {{ hostvars[peer].ansible_enp3s0.ipv4.address if hostvars[peer].ansible_enp3s0.ipv4.address != ansible_enp3s0.ipv4.address }}
      {% endfor %}
        }
        virtual_ipaddress {
          {{ keepalived_vip }}/32 dev enp3s0
        }
        track_process {
          haproxy
        }
      }

</details>