Kiali: Fix Istio Component Statuses

Summary

Adds helm templating to do lookups of the ingressgateways and add their app labels (which are the names) to Kiali's istio component monitoring.

This fixes a bug where previously Kiali would display a red health for istio due to the istio-ingressgateway not existing. By default kiali looks for istiod, istio-ingressgateway, and istio-egressgateway. Since we deploy different ingressgateways (with different labels) this results in an inaccurate health display.

Note that this supports both istio.ingressGateways and istio.values.ingressGateways, in addition to providing the default istiod still. The values for core follow the upstream convention and what we expect BB customers to consider core to their istio deployments (see here). The proxy value is set for only ingress/egress gateways (see here).

Closes https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/675

If you want to test before/after...

helm install from master, you should see a red status dot at the top of kiali that shows the ingressgateway is unreachable

helm upgrade to this branch, you should see

    istio:
      component_status:
        components:
        - app_label: istiod
          is_core: true
          is_proxy: false
        - app_label: public-ingressgateway
          is_core: true
          is_proxy: true

in the kiali spec, and no status dot is in the kiali UI (with healthy status no dot shows up).