docker: find and hide secrets a container printed into its log (hq issue 268)

letta printed two passwords into its log for weeks and nothing noticed,
and docker_logs handed them to whoever asked. docker_secrets_in_logs
compares each container's recent lines with the secret-named values of
its environment, the passwords in its URIs, and any URI carrying a
password, and names what it found by container, module and variable -
never the value. docker_logs redacts the same values before answering.

modules/docker/module.json

@@ -16,6 +16,7 @@
     "docker_list",
     "docker_inspect",
     "docker_logs",
+    "docker_secrets_in_logs",
     "docker_stats",
     "docker_start",
     "docker_stop",