deploy: Use /etc/helmfile-defaults/mediawiki/httpd.yaml from prod

• Rearranged the /etc/helmfile-defaults related files in exp/files/deploy.

• Copied in /etc/helmfile-defaults/mediawiki/httpd.yaml from deploy1002.eqiad.wmnet.

This allows the mw-debug k8s deployment to serve www.mediawiki.org for
testing.

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Related MRs:

• !56 (merged)
• !55 (merged) (This MR)
• !54 (merged)
• main

Depends-On: !54 (merged)