feat: Add ability to use Gravatar as avatar provider (#1319)

Closes #1243

server/api/helpers/users/build-gravatar-url.js

@@ -0,0 +1,26 @@
+/*!
+ * Copyright (c) 2024 PLANKA Software GmbH
+ * Licensed under the Fair Use License: https://github.com/plankanban/planka/blob/master/LICENSE.md
+ */
+
+const crypto = require('crypto');
+
+module.exports = {
+  sync: true,
+
+  inputs: {
+    record: {
+      type: 'ref',
+      required: true,
+    },
+  },
+
+  fn(inputs) {
+    if (!sails.config.custom.gravatarBaseUrl) {
+      return null;
+    }
+
+    const hash = crypto.createHash('md5').update(inputs.record.email).digest('hex');
+    return `${sails.config.custom.gravatarBaseUrl}${hash}?s=180&d=initials`;
+  },
+};