Configure NGINX error log (nginx#319)

Error log will help us understand when and how NGINX gets reloaded
and also see any error messages.
The Debug level is useful while the project is still in the early stage
of development.

Author: miledxz

deploy/manifests/nginx-gateway.yaml

@@ -90,7 +90,7 @@ spec:
       initContainers:
       - image: busybox:1.34 # FIXME(pleshakov): use gateway container to init the Config with proper main config
         name: nginx-config-initializer
-        command: [ 'sh', '-c', 'echo "load_module /usr/lib/nginx/modules/ngx_http_js_module.so; events {}  pid /etc/nginx/nginx.pid; http { include /etc/nginx/conf.d/*.conf; js_import /usr/lib/nginx/modules/njs/httpmatches.js; }" > /etc/nginx/nginx.conf && mkdir /etc/nginx/conf.d /etc/nginx/secrets && chown 1001:0 /etc/nginx/conf.d /etc/nginx/secrets' ]
+        command: [ 'sh', '-c', 'echo "load_module /usr/lib/nginx/modules/ngx_http_js_module.so; events {}  pid /etc/nginx/nginx.pid; error_log stderr debug; http { include /etc/nginx/conf.d/*.conf; js_import /usr/lib/nginx/modules/njs/httpmatches.js; }" > /etc/nginx/nginx.conf && mkdir /etc/nginx/conf.d /etc/nginx/secrets && chown 1001:0 /etc/nginx/conf.d /etc/nginx/secrets' ]
         volumeMounts:
         - name: nginx-config
           mountPath: /etc/nginx