Add `bincode` feature for encoding and decoding with bincode

[ChocolateLoverRaj]

Similar to how there is a serde feature

I implemented this here, but I'm not making a PR because I doubt it will get accepted (mostly cuz it increases the minimum rust version to match the latest bincode's minimum Rust version)

[ada4a]

it increases the minimum rust version to match the latest bincode's minimum Rust version

maybe it would make sense to choose the latest MSRV-compatible version of bincode instead?

[ChocolateLoverRaj]

If we did that that would be bincode 1, which I think does not have its own encoding macros.

[KodrAus]

Thanks for the suggestion! We currently support serde in log because it's a very common interchange library. I don't think we'd likely add direct support for bincode to log itself.

[Thomasdezeeuw]

Per the last comment I'm going to close this.