remote-cp version in zoneInsight

[tharun208]

Make remote kds to send cp version in discovery request metadata

Summary

This PR resolves #1364

Full changelog

• Made remote cp kds to send kuma-cp version in DiscoveryRequest.Node.Metadata
• Updated zoneInsight proto with kuma-cp` version field.
• Updated inspect zones cli to return kuma-cp version.

Issues resolved

Fix #1364

Pending: Update kuma-gui zones view with kuma-cp versions

[jakubdyszkiewicz]

Ok, now I see the value is properly passed and parsed.

But, there is a problem with backward compatibility. I run remote 1.0.3 and see this

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x2aad126]

goroutine 236 [running]:
github.com/kumahq/kuma/pkg/kds/server.readVersion(0x0, 0xc001f15500, 0x3, 0xc0001fc830)
	/Users/jakob/kong/kuma/pkg/kds/server/status_tracker.go:186 +0x26
github.com/kumahq/kuma/pkg/kds/server.(*statusTracker).OnStreamRequest(0xc000879e00, 0x3, 0xc0007f9800, 0x0, 0x0)
	/Users/jakob/kong/kuma/pkg/kds/server/status_tracker.go:126 +0x165
github.com/kumahq/kuma/pkg/util/xds/v2.CallbacksChain.OnStreamRequest(0xc000dfbae0, 0x6, 0xa, 0x3, 0xc0007f9800, 0x1, 0xc00155b790)
	/Users/jakob/kong/kuma/pkg/util/xds/v2/callbacks_chain.go:37 +0x72
github.com/envoyproxy/go-control-plane/pkg/server/sotw/v2.(*server).process(0xc000a0cfc0, 0x2e1f7d58, 0xc001fc0c20, 0xc0006ea9c0, 0x0, 0x0, 0x0, 0x0)
	/Users/jakob/go/pkg/mod/github.com/envoyproxy/go-control-plane@v0.9.8/pkg/server/sotw/v2/server.go:300 +0x1202
github.com/envoyproxy/go-control-plane/pkg/server/sotw/v2.(*server).StreamHandler(0xc000a0cfc0, 0x2e1f7d58, 0xc001fc0c20, 0x0, 0x0, 0x0, 0xc001e29e58)
	/Users/jakob/go/pkg/mod/github.com/envoyproxy/go-control-plane@v0.9.8/pkg/server/sotw/v2/server.go:416 +0xe8
github.com/kumahq/kuma/pkg/kds/server.(*server).StreamKumaResources(0xc0017acd80, 0x39a6300, 0xc001fc0c20, 0xc001f91080, 0xc001623600)
	/Users/jakob/kong/kuma/pkg/kds/server/kds.go:36 +0x8b
github.com/kumahq/kuma/pkg/kds/global.Setup.func1.1(0x397d860, 0xc0017acd80, 0x3998920, 0xc001d3d740, 0x399c640, 0xc001fc0ca0)
	/Users/jakob/kong/kuma/pkg/kds/global/components.go:71 +0x49
created by github.com/kumahq/kuma/pkg/kds/global.Setup.func1
	/Users/jakob/kong/kuma/pkg/kds/global/components.go:70 +0x21f

please add a nil check on metadata itself

func readVersion(metadata *pstruct.Struct, version *system_proto.Version) error {
	if metadata == nil {
		return nil
	}

[tharun208]

if metadata == nil {
return nil
}

@jakubdyszkiewicz, we need to add the nil check to the dataplane_status_tracker.go right ?

[jakubdyszkiewicz]

In Envoy case technically we always had some metadata, but ok - let's maybe add it