Remove duplicate files from ROOT/pages

These files were already moved to dedicated modules but remained
in ROOT/pages after the merge. Removing them to prevent duplicate
alias errors during build.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: JakeSCahill

local-antora-playbook.yml

@@ -13,7 +13,7 @@ output:
 content:
   sources:
   - url: https://github.com/redpanda-data/adp-docs
-    branches: feature/initial-setup
+    branches: main
   - url: https://github.com/redpanda-data/docs
     branches: [main, v/*, api, shared, site-search,'!v-end-of-life/*']
   - url: https://github.com/redpanda-data/cloud-docs