introduce Clear Linux OS to the __docker type

cdist/conf/type/__docker/manifest

@@ -44,6 +44,21 @@ case "$os" in
           exit 1
         fi
     ;;
+    clear-linux-os)
+        if [ "${state}" = present ]
+        then
+            if [ "$version" != latest ]
+            then
+                >&2 echo "Specifying Docker version is unsupported with \"$os\""
+                exit 1
+            fi
+            __package_swupd cloud-control
+        else
+            >&2 echo 'Warning: cowardly refusing to remove "cloud-control", disabling Dockerd instead'
+            __systemd_service docker --state stopped
+            __systemd_unit docker --enablement-state disabled
+        fi
+        ;;
     ubuntu|debian)
       if [ "${state}" = "present" ]; then
         __package apt-transport-https