Somehow combine go-libp2p-crypto and go-libp2p-peer

[Stebalien]

Peer IDs and keys are closely tied together. Unfortunately, they currently live in two separate packages. My current thinking is either:

1. Move crypto into peer (and make a new crypto that depends on peer and re-exports).
2. Combine into go-libp2p-identity and create a new peer and crypto facade.

My motivation is fixing libp2p/specs#111. We need to be bale to deterministically derive peer IDs from keys. That means keys nee to remember their multihash. However, that's a peer-ID concern which doesn't really fit in the current go-libp2p-crypto package.

@raulk this is related to your monorepo suggestion and, IMO, a good start. We could also combine these packages with a few others if we have some other "core" concepts.

Note: fixing libp2p/specs#111 is a rather high priority so I don't want to block it on reworking all of our dependencies.

[Stebalien]

(and libp2p/specs#111 can be fixed, for now, by just getting rid of peer-id inlining and re-introducing it when we add the correct field to the key protobuf).

[vyzo]

I am in favour of having a meta-package for this; crypto is useful outside the concept of peer.

[raulk]

@Stebalien agree it'd be good start to consolidating repos. I don't suppose we'd entertain the idea of moving both peer and crypto to somewhere more central, though?

go-libp2p wouldn't be that place, because clients can instantiate libp2p without importing go-libp2p (ironically), i.e. if they're using BlankHost.

In our current layout, that central place could be go-libp2p-host. You really cannot have libp2p without importing Host; so it's an unconditional dependency.

go-libp2p-host
  |___ id
  |___ crypto
  |___ ...

If somebody really wants to use PeerID outside of libp2p (?), or use our crypto constructs, they can still do so by importing these packages directly.

[Stebalien]

I'm going to take a stab at making a go-libp2p-interfaces package.

[emad-elsaid]

Is there any changes to the implementation or a decision made about this issue?

[Stebalien]

All core interface libraries have been merged into go-libp2p-core.