Merge: DNS settings: add "disable_ipv6"

Closes #473

* commit 'b91753e746c421b0e2bc82e2c2dd5aeb169a5406':
  + client: handle Disable IPv6 setting
  + dns: add "aaaa_disabled" setting

client/src/components/Settings/Dns/Config/Form.js

@@ -65,6 +65,18 @@ let Form = ({
                     />
                 </div>
             </div>
+            <div className="col-12">
+                <div className="form__group form__group--settings">
+                    <Field
+                        name="disable_ipv6"
+                        type="checkbox"
+                        component={renderSelectField}
+                        placeholder={t('disable_ipv6')}
+                        disabled={processing}
+                        subtitle={t('disable_ipv6_desc')}
+                    />
+                </div>
+            </div>
             <div className="col-12">
                 <div className="form__group form__group--settings mb-4">
                     <label className="form__label form__label--with-desc">

client/src/components/Settings/Dns/Config/index.js

@@ -16,6 +16,7 @@ const Config = ({ t, dnsConfig, setDnsConfig }) => {
         blocking_ipv4,
         blocking_ipv6,
         edns_cs_enabled,
+        disable_ipv6,
         processingSetConfig,
     } = dnsConfig;
 
@@ -33,6 +34,7 @@ const Config = ({ t, dnsConfig, setDnsConfig }) => {
                         blocking_ipv4,
                         blocking_ipv6,
                         edns_cs_enabled,
+                        disable_ipv6,
                     }}
                     onSubmit={handleFormSubmit}
                     processing={processingSetConfig}