…option (#521)

* feat(logger): --log-x-real-ip option.
* docs: Updates for --log-x-real-ip.

* refactor: check fallback page path and add log debug if not
* refactor: improve fallback page docs and command description

Before:

$ curl -i "http://localhost:8787/assets?param=123"
HTTP/1.1 308 Permanent Redirect
location: /assets/
vary: accept-encoding
cache-control: public, max-age=86400
content-length: 0
date: Mon, 03 Feb 2025 21:19:19 GMT

After:

$ curl -i "http://localhost:8787/assets?param=123"
HTTP/1.1 308 Permanent Redirect
location: /assets/?param=123
vary: accept-encoding
cache-control: public, max-age=86400
content-length: 0
date: Mon, 03 Feb 2025 21:19:29 GMT