feat: add PROXY protocol support

[casperakos]

I would like to add support for configuring the PROXY protocol in the APISIX helm chart. Currently, the PROXY protocol configuration exists in the template as commented code, but there's no way to enable or configure it via values.yaml.

Motivation

The PROXY protocol allows load balancers to pass client connection information to APISIX. This is especially useful in Kubernetes environments where APISIX is deployed behind a load balancer, and the original client IP needs to be preserved.

Implementation

• [x] Added proxy protocol configuration options to values.yaml with default values:

  proxyProtocol: enabled: false listenHTTPPort: 9181 listenHTTPSPort: 9182 enableTCPPP: false enableTCPPPToUpstream: false

• [x] Updated configmap.yaml to conditionally include proxy_protocol configuration when enabled

• [x] Added schema validation in values.schema.json for the new options

• [x] Updated README.md with documentation for the new configuration options

These changes allow users to easily enable and configure proxy protocol support through the helm chart values, rather than having to manually modify the configmap.

Fixes #812

[muratoreT]

Sorry to just ping you maintainers but any update on this? We are using the PROXY protocol in multiple APISIX deployments and have to manually overwrite the settings on any update or change of them. We'd really appreciate the merge of this PR. Thanks for your work

[muratoreT]

@juzhiyuan @guoqqqi Sorry to ping you but this is opened since mar 4, can you please have a look at the pr? thank you in advance ;)