…tom domain, semi-automatic install with Kustomize) (#139)

* 🚚 Move cert-manager manifests to their own directory

* 🔧 Add Pulumi configs for production

* 🔧 Add Kustomize patch to set Kourier as the ingress class for Knative

* 🔧 Add Kustomize patch to configure the AWS Load Balancer for Knative's Kourier

* 🔧 Add Kustomize patch to set up the domain TLS certificate (generated by cert-manager)

* 🔧 Update Knative domain template, to not include namespace, only app name

* 🔧 Add Kustomize for Knative and Kourier

* 🔧 Add Kustomize configs for domain in staging

* 🔧 Add Kustomize patch for production domain

* 🔨 Update script to deploy Kubernetes resources, including Knative