Implement Deserialize/Serialize for mdns-sd types

[rabbit-time]

Hello. I have found the need to send the data represented by the ResolvedService struct (in my case, over a Unix socket) and thought it would be nice if mdns-sd implemented this.

I know dependencies are a concern, but perhaps a 'serde' feature flag would be in order? Seems like to me it wouldn't be too hard to implement and can mostly be done through derive.

[FelixSelter]

I could do this if desired by the owner

[keepsimple1]

I know dependencies are a concern, but perhaps a 'serde' feature flag would be in order? Seems like to me it wouldn't be too hard to implement and can mostly be done through derive.

Sure, sounds like a good idea to add this as an optional feature with a default off.

I could do this if desired by the owner

That'd be great! Please go ahead. If any questions, please ask in this issue or in your PR. Thanks for helping!