* This controller generates and saves ProxyStateTemplate for sidecar proxies.
* It currently supports single-port L4 ports only.
* It keeps a cache of all destinations to make it easier to compute and retrieve destinations.
* It will update the status of the pbmesh.Upstreams resource if anything is invalid.
* This commit also changes service endpoints to include workload identity. This made the implementation a bit easier as we don't need to look up as many workloads and instead rely on endpoints data.