Update nico_arch_diagram and change it to SVG format

docs/architecture/overview.md

@@ -5,7 +5,7 @@ This page discusses the high level architecture of a site running NVIDIA Infra C
 NICo orchestrates the lifecycle of ["Managed Hosts"](#managed-hosts) and other resources via a set of cooperating control plane services.
 These control plane services have to be deployed to a Kubernetes cluster with a size of at least 3 nodes (for high availability).
 
-![NICo Architecture Diagram](../static/nico_arch_diagram.png)
+![NICo Architecture Diagram](../static/nico_arch_diagram.svg)
 
 The Kubernetes cluster needs to have a variety of services deployed:
 1. [The NICo control plane services](#carbide-control-plane-services). These services are specific to NICo, and must be deployed together in order to allow NICo to manage the lifecycle of hosts.

docs/overview/what-is-nico.md

@@ -35,7 +35,7 @@ NICo's core responsibilities:
 
 ## Architecture overview
 
-![NICo architecture diagram](../static/nico_arch_diagram.png)
+![NICo architecture diagram](../static/nico_arch_diagram.svg)
 
 NICo is deployed as a suite of microservices on a Kubernetes cluster co-located in the datacenter it manages. This suite of microservices forms the control plane, known as the **Site Controller**. The Kubernetes cluster requires a minimum of three nodes for high availability, and all NICo control plane services communicate over mTLS/gRPC.