feat: allow adding extra ports and manifests

[jchanam]

Motivation

In order to add metrics thanks to the plugin https://github.com/freight-hub/verdaccio-openmetrics, we need to expose the ports.

Changes made

• Add a extraPorts value, that contain a list of ports to add to the service and container.
• Add a extraManifests value, that contain a list of kubernetes manifests to deploy within the chart. This is very useful to, for example, add a ServiceMonitor so the service is scraped by prometheus.
• (fix) Add a default name (http) for the service port.

Notes

This is not a breaking change, as the new variables are a list with a default empty one and there is a range to iterate over them.