refactor: add js-libp2p-keychain to the libp2p codebase #388

[vasco-santos]

This PR adds js-libp2p-switch to js-libp2p as a part of #384 and #509 .

Things to note:

• The entire libp2p-keychain history has been added
• Additional commits were made to move switch under ./src/keychain and its tests under ./test/keychain.
• Some of the unneeded files were removed (like LICENSE) since libp2p already has a version of that file
• The readme and package.json from switch were kept, to simplify the transition. Ideally this should all get cleaned up and duplicate tests should be removed in a future PR

Note on Merging:

Right now the plan (obtained from libp2p-keychain PR) is to:

• squash the merge to minimize the commit pollution
• update the readme to point to the original repo
• append the Co-Author list to the squashed commit to maintain author credit
  • This co author list was generated from the libp2p-keychain package.json which is auto generated from the commit history there.

Co-authored-by: Alan Shaw <alan.shaw@protocol.ai>
Co-authored-by: Alberto Elias <hi@albertoelias.me>
Co-authored-by: Alex Potsides <alex@achingbrain.net>
Co-authored-by: David Dias <daviddias.p@gmail.com>
Co-authored-by: Hugo Dias <mail@hugodias.me>
Co-authored-by: Jacob Heun <jacobheun@gmail.com>
Co-authored-by: Maciej Krüger <mkg20001@gmail.com>
Co-authored-by: Masahiro Saito <camelmasa@gmail.com>
Co-authored-by: Richard Schneider <makaretu@gmail.com>
Co-authored-by: Vasco Santos <vasco.santos@moxy.studio>
Co-authored-by: Vasco Santos <vasco.santos@ua.pt>
Co-authored-by: Victor Bjelkholm <victorbjelkholm@gmail.com>

[vasco-santos]

@jacobheun js-libp2p users, such as js-ipfs rely on js-libp2p-keychain directly. I wonder if we should continue that path, and just modify the require, or if we should make this only usable through js-libp2p API. Let me know your thoughts

[vasco-santos]

@jacobheun just rebased this. We should document how to use libp2p-keychain. What do you think to be the best way?

[jacobheun]

js-libp2p users, such as js-ipfs rely on js-libp2p-keychain directly. I wonder if we should continue that path, and just modify the require, or if we should make this only usable through js-libp2p API. Let me know your thoughts.

We should integrate this into the libp2p api, this would likely look like libp2p.keychain, and expose the necessary methods from there. Users shouldn't need to worry about importing this or using it directly it just complicates things.

I would expect users to be able to provide a datastore to libp2p and it would just handle key storage. Users should probably also be able to specify a separate datastore for libp2p-keychain. (We should likely always want these to be "separate" datastores so we're not putting dht/peer/etc data in the same place as our keys).

just rebased this. We should document how to use libp2p-keychain. What do you think to be the best way?

At the bare minimum it needs to be documented in the API and Configuration readme's, and we really need more tests around using this directly with libp2p.

• It would be good to test the persistence. (If Libp2p.create() is given a keystore, it should retain its previous identity instead of creating a new peer id)