Refactor API Schema and validation

- /schema now returns full openapi/swagger schema
- That schema is used to validate incoming requests
- And used as a contract in future integration tests
- Moved route files up one level
- Fixed incorrect 404 reponses when getting objects
- Fixed saving new objects and passing jsonschemavalidation

backend/routes/schema.js

@@ -0,0 +1,38 @@
+const express = require('express');
+const schema  = require('../schema');
+const PACKAGE = require('../package.json');
+
+const router = express.Router({
+	caseSensitive: true,
+	strict:        true,
+	mergeParams:   true
+});
+
+router
+	.route('/')
+	.options((_, res) => {
+		res.sendStatus(204);
+	})
+
+	/**
+	 * GET /schema
+	 */
+	.get(async (req, res) => {
+		let swaggerJSON = await schema.getCompiledSchema();
+
+		let proto = req.protocol;
+		if (typeof req.headers['x-forwarded-proto'] !== 'undefined' && req.headers['x-forwarded-proto']) {
+			proto = req.headers['x-forwarded-proto'];
+		}
+
+		let origin = proto + '://' + req.hostname;
+		if (typeof req.headers.origin !== 'undefined' && req.headers.origin) {
+			origin = req.headers.origin;
+		}
+
+		swaggerJSON.info.version   = PACKAGE.version;
+		swaggerJSON.servers[0].url = origin + '/api';
+		res.status(200).send(swaggerJSON);
+	});
+
+module.exports = router;