Extracted members csv input serialization logic into separate module

refs 772ec13ac49a1d80877bb7b0f90ad57899f868dd

- This is prep work for extraction into members repository.

ghost/members-csv/parse

@@ -0,0 +1,36 @@
+const fsLib = require('../../../../../../lib/fs');
+
+const parse = async (filePath) => {
+    const columnsToExtract = [{
+        name: 'email',
+        lookup: /^email/i
+    }, {
+        name: 'name',
+        lookup: /name/i
+    }, {
+        name: 'note',
+        lookup: /note/i
+    }, {
+        name: 'subscribed_to_emails',
+        lookup: /subscribed_to_emails/i
+    }, {
+        name: 'stripe_customer_id',
+        lookup: /stripe_customer_id/i
+    }, {
+        name: 'complimentary_plan',
+        lookup: /complimentary_plan/i
+    }, {
+        name: 'labels',
+        lookup: /labels/i
+    }, {
+        name: 'created_at',
+        lookup: /created_at/i
+    }];
+
+    return await fsLib.readCSV({
+        path: filePath,
+        columnsToExtract: columnsToExtract
+    });
+};
+
+module.exports.parse = parse;