Add API key auth

https://feedback.yaak.app/p/header-as-auth-option

plugins/auth-apikey/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "@yaak/auth-apikey",
+  "displayName": "API Key Authentication",
+  "description": "Authenticate requests using an API key",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/mountain-loop/yaak.git",
+    "directory": "plugins/auth-apikey"
+  },
+  "private": true,
+  "version": "0.1.0",
+  "scripts": {
+    "build": "yaakcli build",
+    "dev": "yaakcli dev",
+    "lint": "eslint . --ext .ts,.tsx"
+  }
+}