services/horizon: Add LedgerHashStore to Captive-Core config (#4251)

This commit revers LedgerHashStore removed from Horizon's CaptiveCoreConfig in:
b7fde58. This change makes it impossible to PrepareRange using Captive-Core if
there is any other ingestion instance running because CaptiveCoreBackend tries
to load the hash of the ledger from archives when LedgerHashStore is not set.
But ledgers are published every 5 minutes so they contain the hash of the latest
ledger only for a brief amount of time (the moment when checkpoint is
published).

services/horizon/internal/ingest/main.go

@@ -232,6 +232,7 @@ func NewSystem(config Config) (System, error) {
 					NetworkPassphrase:   config.NetworkPassphrase,
 					HistoryArchiveURLs:  []string{config.HistoryArchiveURL},
 					CheckpointFrequency: config.CheckpointFrequency,
+					LedgerHashStore:     ledgerbackend.NewHorizonDBLedgerHashStore(config.HistorySession),
 					Log:                 logger,
 					Context:             ctx,
 				},