kad: rename to follow naming convention across repository

[thomaseizinger]

As tracked in #2217, we should rename the Kademlia behaviour to Behaviour and all related symbols such that users can import it as:

use libp2p::kad;

let b = kad::Behaviour::new(kad::Config::default());

[PanGan21]

Hi @thomaseizinger ! I am interested to contribute this issue. Just one question.
rename the Kademlia behaviour to Behaviour and all related symbols apart from Kademlia -> Behaviour does it mean also to rename KademliaBucketInserts -> BucketInserts, KademliaStoreInserts -> StoreInserts, KademliaConfig -> Config and KademliaCaching -> Caching ?

[thomaseizinger]

Hi @thomaseizinger ! I am interested to contribute this issue. Just one question. rename the Kademlia behaviour to Behaviour and all related symbols apart from Kademlia -> Behaviour does it mean also to rename KademliaBucketInserts -> BucketInserts, KademliaStoreInserts -> StoreInserts, KademliaConfig -> Config and KademliaCaching -> Caching ?

In general, yes!

The goal we want to achieve is a balance between symbol length, expressiveness and ambiguity.

The idea is that users can import the libp2p::kad module and then refer to symbols as kad::Config, kad::Behaviour. I'd suggest to think about it like that and rename symbols such that the combined us with the kad:: prefix makes sense!

To start with, dropping the prefix from all symbols should be good enough. As a 2nd step, I'd recommend going over them and checking, that they still make sense. Depending on how thorough you want to be with that this might require diving into understanding what the protocol does (not sure if you are familiar with Kademlia at all?).

Let us know what your appetite is for working on this and we can set the scope accordingly :)

[thomaseizinger]

Note: We want this to be backwards compatible. I'd suggest reading some of the conversations in PRs linked in #2217.