fix(data): add ruleset to explicitly allow Docker / OCI clients

Fixes #1252

This is technically a regression as these clients used to work in Anubis
v1.22.0, however it is allowable to make this opt-in as most websites do not
expect to be serving Docker / OCI registry client traffic.

Signed-off-by: Xe Iaso <me@xeiaso.net>

data/clients/docker-client.yaml

@@ -0,0 +1,25 @@
+- name: allow-docker-client
+  action: ALLOW
+  expression:
+    all:
+      - path.startsWith("/v2/")
+      - userAgent.contains("docker/")
+      - userAgent.contains("git-commit/")
+      - '"Accept" in headers'
+      - headers["Accept"].contains("vnd.docker.distribution")
+      - '"Baggage" in headers'
+      - headers["Baggage"].contains("trigger")
+
+- name: allow-crane-client
+  action: ALLOW
+  expression:
+    all:
+      - userAgent.contains("crane/")
+      - userAgent.contains("go-containerregistry/")
+
+- name: allow-docker-distribution-api-client
+  action: ALLOW
+  expression:
+    all:
+      - '"Docker-Distribution-Api-Version" in headers'
+      - '!(userAgent.contains("Mozilla"))'