add watchdog support

[tanganellilore]

Hi @vitabaks ,

as requested thi pull request is for add watchdog settings on patroni.

[vitabaks]

Thanks @tanganellilore !

[vitabaks]

Tests error: 'patroni_watchdog' is undefined

TASK [patroni : Generate conf file "/etc/patroni/patroni.yml"] *****************
[675](https://github.com/vitabaks/postgresql_cluster/actions/runs/4084596855/jobs/7042715301#step:5:681)
  changed: [10.172.0.21]
[676](https://github.com/vitabaks/postgresql_cluster/actions/runs/4084596855/jobs/7042715301#step:5:682)
  changed: [10.172.0.20]
[677](https://github.com/vitabaks/postgresql_cluster/actions/runs/4084596855/jobs/7042715301#step:5:683)
  An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ansible.errors.AnsibleUndefinedVariable: 'patroni_watchdog' is undefined. 'patroni_watchdog' is undefined
[678](https://github.com/vitabaks/postgresql_cluster/actions/runs/4084596855/jobs/7042715301#step:5:684)
  fatal: [10.172.0.20]: FAILED! => {"changed": false, "msg": "AnsibleUndefinedVariable: 'patroni_watchdog' is undefined. 'patroni_watchdog' is undefined"}