transactionHandler's GetLedgerRange is not accurate

[2opremio]

It uses the meta table and not the transaction table. The meta table can have a longer history than the transaction table since it stores the maximum range of the events storage window and the transaction storage window.

Also, GetLedgerRange is untested. A test should be added since the function is pretty complex.

The problem was introduced in #174

[2opremio]

Also, we will need to revive the old LedgerRangeGetter to include the event range like we used to in getHealth

[2opremio]

Finally GetLedgerRange is overkill if we only want the Latest Ledger sequence, we can use GetLatestLedger for that.

[aditya1702]

Finally GetLedgerRange is overkill if we only want the Latest Ledger sequence, we can use GetLatestLedger for that.

@2opremio We want both latestLedger and oldestLedger along with their details. I think that is why @Shaptic added this method.

[2opremio]

@2opremio We want both latestLedger and oldestLedger along with their details. I think that is why @Shaptic added this method.

Not for every endpoint (look at the current uses of GetLedgerRange)