implement SkRateLimiterService with Leaky Bucket rate limiting

packages/backend/src/core/EnvService.ts

@@ -0,0 +1,20 @@
+/*
+ * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Injectable } from '@nestjs/common';
+
+/**
+ * Provides access to the process environment variables.
+ * This exists for testing purposes, so that a test can mock the environment without corrupting state for other tests.
+ */
+@Injectable()
+export class EnvService {
+	/**
+	 * Passthrough to process.env
+	 */
+	public get env() {
+		return process.env;
+	}
+}