Use port number instead of name for k8s service port

[Xinayder]

I've found an issue when deploying Dendrite's Helm chart on my local cluster. The template for generating an Ingress resource tries to find the service port using a name (http), but the template that generates the Service resource, instead, identifies the resource with a port number.

According to the Kubernetes ServiceSpec, ports.targetPort can be either a number or a string; if it's the latter, it will be looked up as a named port in the pod's container ports.

Pull Request Checklist

• [x] I have added Go unit tests or Complement integration tests for this PR or I have justified why this PR doesn't need tests
• [x] Pull request includes a sign off below using a legally identifiable name or I have already signed off privately

[Xinayder]

I did some more testing and it turns out that even if you set the targetPort property on the Service definition, the ingress controller won't find the pod.

However, if you set the service.port property on the ingress resource to the port number, it works. If it's set to http, it doesn't.

[InezMc]

Confirm that private signoff recieved.

[Xinayder]

~~Still haven't received an email back from Matrix regarding my private signoff request.~~

[Xinayder]

Sign-off confirmed.