Install multiple instances of Tekton on a single K8s cluster

Feature request

Currently there can only be one instance of Tekton installed on a K8s cluster. It would be useful if we could install multiple instances on a cluster (in different namespaces).

Use case

This would be beneficial in a multi-tenancy cluster environment where each tenant is provisioned with a unique namespace. Ideally, we would install a separate instance for each tenant which would run in their provisioned namespace and not interfere with other instances on the cluster. It would make sense in this scenario that each instance only watches one namespace (the namespace it belongs to).