www/nginx-module-ndk: Update to 0.3.5

Switch to the openresty fork. The repository at vision5 has seen no
commit since February 2025, while openresty carries the fix for complex
values with nginx 1.31.3, which www/nginx-devel needs, and is the tree
that the CI of the modules depending on the NDK clones.

Follow the layout of the other module source ports and add a pkg-message
that explains how the nginx ports turn the sources into
ndk_http_module.so.

Sponsored by: Netzkommune GmbH