Full plugins and server redesign

- Languages, issues and pr are now plugins (but enabled by default for retro-compatibility)
- Query parameters are now parsed correctly
- Redesigned server index with vue.js

package.json

@@ -7,7 +7,7 @@
     "start": "node index.mjs",
     "build": "node utils/build.mjs",
     "test": "node tests/metrics.mjs",
-    "upgrade": "npm install @actions/core@latest @actions/github@latest @octokit/graphql@latest @octokit/rest@latest axios@latest compression@latest ejs@latest express@latest express-rate-limit@latest image-to-base64@latest memory-cache@latest svgo@latest @vercel/ncc@latest libxmljs@latest"
+    "upgrade": "npm install @actions/core@latest @actions/github@latest @octokit/graphql@latest @octokit/rest@latest axios@latest compression@latest ejs@latest express@latest express-rate-limit@latest image-to-base64@latest memory-cache@latest svgo@latest vue@latest @vercel/ncc@latest libxmljs@latest"
   },
   "repository": {
     "type": "git",
@@ -31,7 +31,8 @@
     "express-rate-limit": "^5.1.3",
     "image-to-base64": "^2.1.1",
     "memory-cache": "^0.2.0",
-    "svgo": "^1.3.2"
+    "svgo": "^1.3.2",
+    "vue": "^2.6.12"
   },
   "devDependencies": {
     "@vercel/ncc": "^0.24.1",