Problem: need to add JSON-RPC endpoint personal_listWallets

[adu-web3]

Closes #745

• wallet level that manages accounts is not supported by keyring interface, will return nil

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[fedekunze]

linter is failing @Muggle-Du

[adu-web3]

linter is failing @Muggle-Du

I see, but geth implement ListWallets in the same way.
Or should I make rawWallet public by replacing with RawWallet?

[adu-web3]

lint failure fixed @fedekunze