NewLedgerMgr creates a new LedgerMgr.

ErrLedgerAlreadyOpened is thrown by a CreateLedger call if a ledger with the given id is already opened.

ErrLedgerMgmtNotInitialized is thrown when ledger mgmt is used before initializing this.

Initializer encapsulates all the external dependencies for the ledger module.

LedgerMgr manages ledgers for all channels.