refine datdot architecture

[serapath]

@todo

• compare with https://github.com/ipfs/specs/blob/master/KEYCHAIN.md
• compare vault/wallet with https://github.com/ipfs/specs/blob/master/KEYSTORE.md
• compare with https://github.com/ipfs/specs/blob/master/REPO.md
  • and https://github.com/ipfs/specs/blob/master/REPO_FS.md
• compare with https://github.com/ipfs/specs/blob/master/DWEB_ADDRESSING.md

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