[CodeGen React UI] Support parametrization of nginx port

[Feelas]

In the nginx.conf for CodeGen React UI, there is a hardcoded port 80.

GenAIExamples/CodeGen/docker/ui/react/nginx.conf

Line 2 in 09a3196

listen 80;

Supporting parametrization of nginx port is not a purely cosmetic matter, since it causes issues on unpriviliged deployments on K8s/OpenShift.

It would be good to both:

• switch the default from port 80 to a known-working port outside of 1-1023 range, since it is is privileged by default and requires specific securityContext (which would be a terrible thing to use).
• support parametrizing nginx port in an easy way, which doesn't require rebuilding the image (see the docs for upstream image used: https://hub.docker.com/_/nginx -> Using environment variables in nginx configuration (new in 1.19))

The fastest way to fix the issue would be to just switch port 80 to 8080.

Additionally, might be good to look into using https://hub.docker.com/r/nginxinc/nginx-unprivileged image as base.

[lianhao]

Agreed. When fixing this, please also fix https://github.com/opea-project/GenAIComps/blob/main/comps/third_parties/nginx/src/nginx.conf.template at the same time.

[xiguiw]

• witch the default from port 80 to a known-working port outside of 1-1023 range, since it is is privileged by default and requires specific securityContext (which would be a terrible thing to use).

Per @lianhao. It is not permitted to run with privileged/root for some public K8S

[xiguiw]

@jaswanth8888

It decreases the security of OPEA. This is a critical issue.
Pleased resolve is ASAP.

[yinghu5]

Link Support parametrization of nginx port #1456
Just Remind @jaswanth8888 @ZePan110 , hopefully the PR can fix the issues.