fix: implement String for logging of PodInfo and IPConfig

[rbtr]

Reason for Change:

Adds String() to PodInfo so that logging the interface type works.
Currently, logging with %[+]v will insert the interface address in to the string instead of the values of the underlying type:

... ipState: {ID:abc IPAddress:123.456.789.0 LastStateTransition:2023-06-15 05:30:57.855233208 +0000 UTC m=+4.301209489 NCID:def PodInfo:0xc000529ae0 state:Assigned stateMiddlewareFuncs:[0x164faa0]}

Note:

PodInfo:0xc000529ae0

and (impl detail which should be removed)

stateMiddlewareFuncs:[0x164faa0]

With String() implemented on both types, loggers may use %s and get correctly formatted and populated output for the underlying types:

... ipState: {ID: [abc], NCID: [def], IPAddress: [123.456.789.0], State: [Assigned], LastStateTransition: [2023-06-16T21:26:43Z] PodInfo: [InfraContainerID: [pqr], InterfaceID: [mno], Key: [mno], Name: [ghi], Namespace: [jkl]]

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests
• relevant PR labels added

Notes: