mysql: expose IPv6 configuration to mysql puppet modules

When deploying on IPv6 networks, set a hiera key that can be consumed
by puppet modules to configure MySQL or Galera appropriately.

Currently, this is required for configuring SST encryption in Galera
when Internal TLS is enabled [1].

[1] I1d6ee8febb596b3ab9dcde3a85a028ee99b2798c

Change-Id: Ia857350ac451fc1bda6659d85019962d3a9d5617
Partial-Bug: #1719885

environments/network-isolation-v6.j2.yaml

@@ -55,3 +55,5 @@ parameter_defaults:
   RabbitIPv6: True
   # Enable IPv6 environment for Memcached.
   MemcachedIPv6: True
+  # Enable IPv6 environment for MySQL.
+  MysqlIPv6: True

puppet/services/database/mysql.yaml

@@ -57,6 +57,11 @@ parameters:
   EnableInternalTLS:
     type: boolean
     default: false
+  MysqlIPv6:
+    default: false
+    description: Enable IPv6 in MySQL
+    type: boolean
+
 
 conditions:
 
@@ -77,6 +82,7 @@ outputs:
             # in tripleo-puppet-elements.
             mysql::server::package_name: 'mariadb-galera-server'
             mysql::server::manage_config_file: true
+            mysql_ipv6: {get_param: MysqlIPv6}
             tripleo.mysql.firewall_rules:
               '104 mysql galera':
                 dport: