Archive systemcerts repo

We are not using it anymore, yay!

Author: mariash

org/cloudfoundry.yml

@@ -2265,6 +2265,7 @@ orgs:
         default_branch: main
         has_projects: true
       systemcerts:
+        archived: true
         allow_merge_commit: false
         has_issues: false
         has_projects: true

toc/working-groups/app-runtime-platform.md

@@ -132,7 +132,6 @@ areas:
   - cloudfoundry/route-emitter
   - cloudfoundry/runtime-credentials
   - cloudfoundry/sample-http-app
-  - cloudfoundry/systemcerts
   - cloudfoundry/tlsconfig
   - cloudfoundry/vizzini
   - cloudfoundry/volman