Helm chart: Define port for NodePort

[alphayax]

Initial problem

When installing the chart on my microk8s cluster, I use NodePort to make Plex accessible from internet. But, the port is randomly defined, and can change at any time.

This PR Solution

Add the ability to define the node port to use when service is NodePort. Default is 32400.

• When service = NodePort, the nodePort will automatically be 32400 by default.
• If user want to override and define is own node port, he can define the .Value.service.nodePort value to whatever he want

[cilindrox]

LGTM 👍

[cilindrox]

Thanks @alphayax - could you bump the version to a minor (0.2.0) so we can release this?