chore: update codeowners and catalog-info.yaml to DX

Author: whitelisab

.github/CODEOWNERS

@@ -1,4 +1,4 @@
-* @contentful/team-tundra
+* @contentful/team-tundra @contentful/team-developer-experience
 
 package.json
 package-lock.json

catalog-info.yaml

@@ -7,8 +7,11 @@ metadata:
   annotations:
     circleci.com/project-slug: github/contentful/contentful.js
     github.com/project-slug: contentful/contentful.js
-    contentful.com/ci-alert-slack: prd-extensibility-bots
+    contentful.com/ci-alert-slack: prd-ecosystem-dx-bots
+    contentful.com/service-tier: '4'
+  tags:
+    - tier-4
 spec:
   type: library
   lifecycle: production
-  owner: group:team-tundra
+  owner: group:team-developer-experience