fix: add form padding, validators for /configure pages

src/wuttaweb/templates/configure.mako

@@ -9,7 +9,9 @@
 
   ${h.form(request.current_route_url(), enctype='multipart/form-data', ref='saveSettingsForm', **{'@submit': 'saveSettingsFormSubmit'})}
     ${h.csrf_token(request)}
+    <div class="wutta-form-wrapper">
       ${self.form_content()}
+    </div>
   ${h.end_form()}
 
   <b-modal has-modal-card
@@ -148,8 +150,18 @@
     ThisPageData.settingsNeedSaved = false
     ThisPageData.undoChanges = false
     ThisPageData.savingSettings = false
+    ThisPageData.validators = []
 
     ThisPage.methods.saveSettings = function() {
+
+        for (let validator of this.validators) {
+            let msg = validator.call(this)
+            if (msg) {
+                alert(msg)
+                return
+            }
+        }
+
         this.savingSettings = true
         this.$refs.saveSettingsForm.submit()
     }