Add istio gateway template

[yciabaud]

Hi there I made a little addition to your project, I made a PR from it it you are interested in it too.

This adds the ability to create a istio gateway crd to expose istio services in an ingress gateway.

[goruha]

@yciabaud awesome.
Thanks for the PR.
I did not work with istio.
Do we need one gateway per chart or it would be better to have a list of gateways?

[aknysh]

see comments

[yciabaud]

Sorry I forgot to come back here for a while, I have updated my PR, feel free to have a look at it.

[osterman]

Should we add [] since the list is commented out?

Suggested change

	istio_gateways:
	istio_gateways: []

[osterman]

@goruha 👆

[goruha]

@yciabaud I think we should change the pattern now istio_gateways defined

istio_gateways:
  gateway1:
    enabled: true
    selector:
      istio: istio-gateway
    servers:
    - hosts:
      - '*.domain.com'
      port:
        name: http
        number: 80
        protocol: HTTP
      tls:
        httpsRedirect: true
    - hosts:
      - '*.domain.com'
      port:
        name: http-tls
        number: 443
        protocol: HTTP
      tls:
        mode: SIMPLE
        privateKey: /etc/istio/ingressgateway-certs/tls.key
        serverCertificate: /etc/istio/ingressgateway-certs/tls.crt

[goruha]

check the comments