Account Export/Import

[holtzman]

Is your feature request related to a problem? Please describe.
The full-service wallet-db contains information about each account that is not on the blockchain, for example, transaction logs for outbound payments, nicknames for accounts, and mappings between subaddresses and contacts.

full-service also keeps a contacts database with b58 addresses.

If you want to move accounts between wallets, you can export the mnemonic, but all of the rest of the information is lost.

Also, while you can backup your wallet-db as binary files, in case something goes wrong, this backup is opaque and just as fragile as the original db, so if something goes wrong, likely you lose all of the non-blockchain data.

Describe the solution you'd like
This feature request proposes adding export and import end-points to full-service that would allow one to backup their accounts and contacts in json files so that a full-service account or contact list could be:

• moved from wallet to wallet, e.g. the operator might have accounts in 3 different instances of full-service and want to combine these to a single instance, or vice-versa.
• back up (and restore) accounts and contacts in a non-binary format so that data can be examined, corrected, and recovered in the case of a bug or corruption issue.
• support the migration of accounts and contacts between platforms and possibly between different wallet applications
• allow for replication of mnemonics on multiple machines for availability purposes, and the merging of transaction logs between those machines.

Describe alternatives you've considered
Frequently backing up the wallet-db binary files is the only alternative now, and does not support the reconfiguration of accounts that are served by each wallet in a lossless way. Also, there is no way to combine account data from different points in time using this method, e.g. from time-to-time operators needing immediate access to funds will restore mnemonics on a remote machine in order to transact and then want to merge those transaction logs back to the main machine when it is available again, but there is no way to do this currently.