dev-api: add developer portal, OpenAPI spec, and Flatenbadet case study

- New /developers/ page with API docs, SDKs, pricing, use cases
- OpenAPI 3.0 spec for Orders, Missions, Photos, Analytics
- Case study: Glasskiosken i Flatenbadet — complete ROI analysis
- Updated /order/ with recurring missions and frequency dropdown

services/frilans-payout/node_modules/json-stable-stringify-without-jsonify/example/value_cmp.js

@@ -0,0 +1,7 @@
+var stringify = require('../');
+
+var obj = { d: 6, c: 5, b: [{z:3,y:2,x:1},9], a: 10 };
+var s = stringify(obj, function (a, b) {
+    return a.value < b.value ? 1 : -1;
+});
+console.log(s);