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

src/plugins/index.mjs

@@ -1,5 +1,7 @@
 //Imports
+  import followup from "./followup/index.mjs"
   import habits from "./habits/index.mjs"
+  import languages from "./languages/index.mjs"
   import lines from "./lines/index.mjs"
   import pagespeed from "./pagespeed/index.mjs"
   import selfskip from "./selfskip/index.mjs"
@@ -7,7 +9,9 @@
 
 //Exports
   export default {
+    followup,
     habits,
+    languages,
     lines,
     pagespeed,
     selfskip,