Add interface names into NSM metrics

[VitalyGushin]

In the forwarder's "metrics" field add 4 interfaces as key-value pairs with the key names: "interface_client", "interface_client_fwd", "interface_endpoint", "interface_endpoint_fwd", and with a value in the format "interface-type/interface-name".
Example of a Connection:

[dualBreath]

I can't change the original description, so I'll post the actual state of the solution here.

The solution is presented schematically in this diagram:

1. NSC metrics contains a single field "client_interface" with value in the format "interface-type/interface-name", for example:
   "client_interface": "MEMIF/nsm-1"
2. NSE metrics contains a single field "server_interface" with value in the format "interface-type/interface-name", for example:
   "server_interface": "KERNEL/memif2kern-672c"
3. Forwarder metrics contains a pair of fields "client_interface", "server_interface" with values in the format "interface-type/interface-name", for example:
   "server_interface": "MEMIF/memif1013904223/0"
"client_interface": "VIRTIO/tap0"

Thus, metrics related to NSC, NSE and Forwarder are printed in separate sections of the path.

Some cases that may cause problems when reading this data:

1. interface name may contain /, for example:
   memif1013904223/0
2. interface type may contain spaces, for example:
   WIREGUARD TUNNEL

All information can be found in the NSC request-response, for example Kernel2Memif use-case NSC logs:

{
    "id": "alpine-395ed7f9-30fd-41aa-af2d-1c5d6ca8889b-0",
    "network_service": "kernel2memif",
    "mechanism": {
        ...
    },
    "context": {
        ...
    },
    "labels": {
        ...
    },
    "path": {
        "path_segments": [
            {
                "name": "alpine-395ed7f9-30fd-41aa-af2d-1c5d6ca8889b",
                ...
                "metrics": {
                    "client_interface": "KERNEL/nsm-1"
                }
            },
            {
                "name": "nsmgr-8ckqf",
                ...
            },
            {
                "name": "forwarder-vpp-5x4ck",
                ...
                "metrics": {
                    "client_drops": "0",
                    "client_interface": "MEMIF/memif1013904223/0",
                    "client_rx_bytes": "0",
                    "client_rx_packets": "0",
                    "client_tx_bytes": "516",
                    "client_tx_packets": "6",
                    "server_drops": "0",
                    "server_interface": "VIRTIO/tap0",
                    "server_rx_bytes": "516",
                    "server_rx_packets": "6",
                    "server_tx_bytes": "0",
                    "server_tx_packets": "0"
                }
            },
            {
                "name": "nse-memif-7948d8d869-mwnq8",
                ...
                "metrics": {
                    "server_interface": "MEMIF/memif1013904223/0"
                }
            }
        ]
    },
    "network_service_endpoint_name": "nse-memif-7948d8d869-mwnq8",
    "payload": "ETHERNET"
}

I've posted more output examples here: networkservicemesh/sdk#1560 (comment)

IMPORTANT NOTE
In case of Memif connection to Memif Forwarder is not used and we cannot see any metrics there, for example Memif2Memif use-case NSC output:

{
    "id": "nsc-memif-76699ccbc7-x9xhf-0",
    "network_service": "memif2memif",
    "mechanism": {
        ...
    },
    "context": {
        ...
    },
    "labels": {
        ...
    },
    "path": {
        "path_segments": [
            {
                "name": "nsc-memif-76699ccbc7-x9xhf",
                ...
                "metrics": {
                    "client_interface": "MEMIF/nsm-1"
                }
            },
            {
                "name": "nsmgr-t529n",
                ...
            },
            {
                "name": "forwarder-vpp-7tjb2",
                ...
            },
            {
                "name": "nse-memif-7ccff8bf8-2wghn",
                ...
                "metrics": {
                    "server_interface": "MEMIF/memif1013904223/0"
                }
            }
        ]
    },
    "network_service_endpoint_name": "nse-memif-7ccff8bf8-2wghn",
    "payload": "ETHERNET"
}

[dualBreath]

@VitalyGushin please take a look and confirm if you agree with the new details of the solution

[VitalyGushin]

LGTM

[NikitaSkrynnik]

No interface names on memif clients (vl3 nses probably too)