[Web] move domain-wide-footer vars info to lang files

data/web/lang/lang.en-gb.json

@@ -586,6 +586,13 @@
         "domain_footer": "Domain wide footer",
         "domain_footer_html": "HTML footer",
         "domain_footer_info": "Domain-wide footers are added to all outgoing emails associated with an address within this domain. <br> The following variables can be used for the footer:",
+        "domain_footer_info_vars": {
+            "auth_user": "{= auth_user =}   - Authenticated Username specified by an MTA",
+            "from_user": "{= from_user =}   - From user part of envelope, e.g for \"moo@mailcow.tld\" it returns \"moo\"",
+            "from_name": "{= from_name =}   - From name of envelope, e.g for \"Mailcow &lt;moo@mailcow.tld&gt;\" it returns \"Mailcow\"",
+            "from_addr": "{= from_addr =}   - From address part of envelope",
+            "from_domain": "{= from_domain =} - From domain part of envelope"
+        },
         "domain_footer_plain": "PLAIN footer",
         "domain_quota": "Domain quota",
         "domains": "Domains",

data/web/templates/edit/domain.twig

@@ -281,11 +281,11 @@
                   <div class="col-sm-12">
                     <h4>{{ lang.edit.domain_footer }}</h4>
                     <p>{{ lang.edit.domain_footer_info|raw }}</p>
-                    <pre>{= auth_user =}   - Authenticated Username specified by an MTA
-{= from_user =}   - Parsed user part of email headers, e.g for "moo@mailcow.tld" it returns "moo"
-{= from_name =}   - Parsed name of email headers, e.g for "Mailcow &lt;moo@mailcow.tld&gt;" it returns "Mailcow"
-{= from_addr =}   - Parsed address part of email headers
-{= from_domain =} - Parsed domain part of email headers</pre>
+                    <pre>{{ lang.edit.domain_footer_info_vars.auth_user }}
+{{ lang.edit.domain_footer_info_vars.from_user }}
+{{ lang.edit.domain_footer_info_vars.from_name }}
+{{ lang.edit.domain_footer_info_vars.from_addr }}
+{{ lang.edit.domain_footer_info_vars.from_domain }}</pre>
                     <form class="form-horizontal mt-4" data-id="domain_footer">
                       <div class="row mb-2">
                         <label class="control-label col-sm-2" for="domain_footer_html">{{ lang.edit.domain_footer_html }}:</label>