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/eslint/messages/invalid-rule-severity.js

@@ -0,0 +1,13 @@
+"use strict";
+
+const { stringifyValueForError } = require("./shared");
+
+module.exports = function({ ruleId, value }) {
+    return `
+Configuration for rule "${ruleId}" is invalid. Expected severity of "off", 0, "warn", 1, "error", or 2.
+
+You passed '${stringifyValueForError(value, 4)}'.
+
+See https://eslint.org/docs/latest/use/configure/rules#using-configuration-files for configuring rules.
+`.trimStart();
+};