snapshots should contain message receipts

[hanabi1224]

Issue summary

We should have an option to generate snapshots that include message receipts, to facilitate RPC parity tests against lotus, since lotus daemon --import-snapshot does not validate and re-generate message receipts and lotus daemon --import-chain validates all tipsets back to genesis which does not work with lite snapshots

Lotus code:

if !skipMsgReceipts && walked.Visit(b.ParentMessageReceipts) {
    out = append(out, b.ParentMessageReceipts)
}

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