Improve README (#17)

* Add helper tag

* Fix source reference

* Add icons

* Update code-server README

* Update README for contributing

* Update README

* Improve readme

* Fix code-server without extensions

personalize/README.md

@@ -1,7 +1,7 @@
 ---
 display_name: Personalize
 description: Allow developers to customize their workspace on start
-icon: ../icons/personalize.svg
+icon: ../.icons/personalize.svg
 maintainer_github: coder
 verified: true
 tags: [helper]

personalize/main.tf

@@ -3,7 +3,7 @@ terraform {
 
   required_providers {
     coder = {
-      source  = "terraform.local/coder/coder"
+      source  = "coder/coder"
       version = ">= 0.12"
     }
   }