acme: domain edit: allow setting the alias of DNS domains

Domains validated with the DNS challenge can have an alias, so that the
challenge record is created on another domain, which the
'_acme-challenge' record of the domain points to with a CNAME.

But the alias could only be set on the CLI, as the edit window only
kept an existing one in a hidden field. Show it as a text field for
domains with the DNS challenge type, like the plugin.

As a side effect, an existing alias is not kept anymore when switching
a domain to the HTTP challenge type with separate domain entries, like
it is done in Proxmox Mail Gateway, where it has no meaning.

Signed-off-by: Michal Fox <me@dualfroz.com>

src/window/ACMEDomains.js

@@ -142,16 +142,14 @@ Ext.define('Proxmox.window.ACMEDomainEdit', {
                         change: function (cb, value) {
                             let me = this;
                             let view = me.up('pmxACMEDomainEdit');
-                            let pluginField = view.down('field[name=plugin]');
-                            pluginField.setDisabled(value !== 'dns');
-                            pluginField.setHidden(value !== 'dns');
+                            for (const name of ['plugin', 'alias']) {
+                                let field = view.down(`field[name=${name}]`);
+                                field.setDisabled(value !== 'dns');
+                                field.setHidden(value !== 'dns');
+                            }
                         },
                     },
                 },
-                {
-                    xtype: 'hidden',
-                    name: 'alias',
-                },
                 {
                     xtype: 'pmxACMEPluginSelector',
                     name: 'plugin',
@@ -170,6 +168,14 @@ Ext.define('Proxmox.window.ACMEDomainEdit', {
                     value: '',
                     fieldLabel: gettext('Domain'),
                 },
+                {
+                    xtype: 'proxmoxtextfield',
+                    name: 'alias',
+                    disabled: true,
+                    hidden: true,
+                    fieldLabel: gettext('Alias'),
+                    emptyText: Proxmox.Utils.noneText,
+                },
                 {
                     xtype: 'combobox',
                     name: 'usage',