feat(p2p): add versioned handlers function

[janos]

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Description

This PR adds VersionedHandler and NewVersionedHandlersFunc to pkg/p2p to streamline protocol backward compatibility across node versions. The suggestion for this feature came from @acud.

When updating protocols while maintaining support for older node releases, checking stream versions manually inside handler bodies can get verbose. NewVersionedHandlersFunc provides a clean, declarative way to associate handlers with minimum semver thresholds.

When using NewVersionedHandlersFunc function it is needed to declare legacy handlers with the versions of the protocol from which that handler is supported and new handlers to define from which version of the protocol it is supported, so the function will select the highest supported handler by the peer's stream. The implementation relies on the recently added Stream.Version() method to get the version of the stream. This function can be used for both handler and "client" functions, as the logic is the same. There is an example added for more clarity on the usage.

Open API Spec Version Changes (if applicable)

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