feat: dns challenge

defaults/main.yml

 ---
 # certbot settings
+certbot_dns_challenge: false                                                          # default use webserver, true to obtain certificate using dns challenge
+certbot_lego_version: "4.11.0"                                                        # lego version - Let's Encrypt client
+certbot_dns_provider: "designate"                                                     # list of available providers https://go-acme.github.io/lego/dns/
+dns_provider_auth_env_variables:                                                      # variables required to authenticate dns provider
+  OS_AUTH_URL: "https://openstack.example.org"
+  OS_REGION_NAME: "RegionOne"
+  OS_AUTH_TYP: "v3applicationcredential"                                              # default is to use application credential rather than password
+  OS_APPLICATION_CREDENTIAL_ID: "{{ vault_os_application_credential_id }}"
+  OS_APPLICATION_CREDENTIAL_SECRET: "{{ vault_os_application_credential_secret }}"
+
+
 certbot_fqdn:
   - example.de
 certbot_admin_email: "admin@example.de"
-# certbot_webroot: "/var/www/example"                          # if undefined use --standalone
+# certbot_webroot: "/var/www/example"                                                 # if undefined use --standalone
 
 # application settings
-# certbot_application: "example"                               # if defined copy certs to application dir and setup deploy hooks
+# certbot_application: "example"                                                      # if defined copy certs to application dir and setup deploy hooks
 certbot_application_dir: "/etc/{{ certbot_application }}"
 certbot_application_deploy_hook: |
   #!/bin/sh