improve allowlist logging

[wollomatic]

1. If the default allowlist ist empty, output that instead of printing out an empty list:

dockerproxy-1  | Default request allowlist:
dockerproxy-1  |    Method   Regex
dockerproxy-1  | time=2026-05-03T13:37:15.115Z level=INFO msg="socket-proxy running and listening..."

2. Clearer output of multple allows. Currently, the separation with only one whitespace is confusing:

dockerproxy-1  |    GET      [^/v1\..{2}/info$ ^/v1\..{2}/images/.*$ ^/v1\..{2}/version$ ^/v1\..{2}/containers/.*$]