Add separate how bitswap works doc

[dirkmc]

No description provided.

[daviddias]

@dirkmc this is great. Can you add some architecture diagrams like https://github.com/ipfs/js-ipfs-bitswap#structure ?

[dirkmc]

I'm a little wary of adding an architecture diagram, as they tend to quickly become out of date as the code is refactored. My preference is to have really good documentation in the code itself.

How do you feel about the pros / cons @daviddias ?

[Stebalien]

I'd like to add a general architecture diagram, but for different reasons. Making an architecture diagram will let us plan the next refactor. That is:

1. Diagram the current architecture.
2. Play with it to create the architecture we want.
3. Refactor.
4. Diagram the result.

[dirkmc]

Ok fair enough I'll do that

[dirkmc]

I updated the existing architecture diagram and added an Implementation section. Let me know if that's enough detail, otherwise I can add some more

[dirkmc]

I'm going to merge this in as it's been open for a while and seems to be in a good state. We can make further documentation improvements in new PRs.