toolkit: override email VType validation

ExtJS email validation regex has a length limit of 6 on the TLD.
This breaks some new gTLDs (e.g. .systems)

Override the validation function and verify against the EMAILRE from
PVE::Tools (used for 'e-mail' in JSONSchema)

Reported in our community forum:
https://forum.proxmox.com/threads/acme-account-register-dialog-does-not-accept-gtlds.87305/

Quickly tested (by using test@test.systems(|test)? on my test-installation)

Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>

src/Toolkit.js

@@ -182,6 +182,11 @@ Ext.apply(Ext.form.field.VTypes, {
     },
 
     passwordText: gettext('Passwords do not match'),
+
+    email: function(value) {
+	let emailre = /^[\w+~-]+(\.[\w+~-]+)*@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)$/;
+	return emailre.test(value);
+    },
 });
 
 // Firefox 52+ Touchscreen bug