rpm: proxy RPM Fusion free/nonfree remotes

The rpmfusion-free / rpmfusion-nonfree repos have no artifactapi remote,
so nodes still point at the retired packagerepo.service.consul mirror and
dnf fails to fetch repomd.xml.

Add caching remote proxies for both trees, pointed at the upstream
download1.rpmfusion.org origin, so el nodes can install RPM Fusion
packages (ffmpeg, etc.) through artifactapi.

Claude-Session: https://claude.ai/code/session_01VZ81u2JtjvaPq8Z3EDTSMb

config/remote_rpm/rpmfusion-free.yaml

@@ -0,0 +1,9 @@
+base_url: https://download1.rpmfusion.org/free
+description: RPM Fusion free RPM package repository
+immutable_ttl: 0
+mutable_ttl: 7200
+immutable_patterns:
+  - ".*\\.rpm$"
+  - ".*/repodata/.*\\.xml.*$"
+  - ".*/repodata/.*\\.sqlite.*$"
+  - "RPM-GPG-KEY-.*$"

config/remote_rpm/rpmfusion-nonfree.yaml

@@ -0,0 +1,9 @@
+base_url: https://download1.rpmfusion.org/nonfree
+description: RPM Fusion nonfree RPM package repository
+immutable_ttl: 0
+mutable_ttl: 7200
+immutable_patterns:
+  - ".*\\.rpm$"
+  - ".*/repodata/.*\\.xml.*$"
+  - ".*/repodata/.*\\.sqlite.*$"
+  - "RPM-GPG-KEY-.*$"