Add support for proxy protocol with the `gitlab-sshd` daemon option.

Summary

When using the gitlab-sshd daemon option there is no way currently to configure the proxy_protocol support.
The daemon has the config option here.
Unfortunately it is not configurable via an environment variable at this stage as per the config here.

Proposal

Add a configuration option to the config map sshd block here

Update the values.yaml to include config.proxyProtocol: false as a default option.

Steps to reproduce

Use gitlab-sshd option with the chart here

Configuration used

Shell config:

gitlab-shell:
  sshDaemon: gitlab-sshd

Current behavior

Can not enable proxy_protocol with gitlab-sshd.

Expected behavior

Be able to enable proxy_protocol when gitlab-sshd is used as a daemon option.

Versions

• Chart: 5.3.0
• Platform:
  • Cloud: EKS
• Kubernetes: (kubectl version)
  • Client: v1.19.11"
  • Server: v1.19.13-eks-8df270
• Helm: (helm version)
  • Client: v3.6.0"