DHT module docs

[ThetaSinner]

This PR now does three things. Some minor code cleanup and documentation consistency for existing code. Then I've also added some top level crate docs with diagrams and started a glossary. Initially this PR just had the glossary.

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It might be too early for this, just thinking about where to put the glossary of terms that @zippy asked for. I think it's a good idea, we've already got a bunch of terms we use that wouldn't be clear to anybody who didn't work on Kitsune1 :)

I'm thinking the API is a decent place. Everything will have a trail back to the API, it's the starting point for anybody integrating with Kitsune2.
A better place might be the main module (the equivalent of kitsune_p2p) because that's where we'll have the maximum number of dependencies available to use for type references.

Doing a glossary like this, we get nice easy to reference links to terms -> file:////kitsune2/target/doc/kitsune2_api/doc/glossary/index.html#time-slice

[jost-s]

Yeah, that's good. I think api crate and main crate are equally valid places for this. Slight preference for main crate.

[ThetaSinner]

I think I prefer the main crate too. I will commit to moving this module there once it exists and for now, I'll add to this? :)

[jost-s]

sure!

[ThetaSinner]

I'll continue this after #59

[neonphog]

Suggestion: #66

[neonphog]

Some different options for the build.rs and svgs. All the text and changes look good to me!

[neonphog]

🎉