[pulsar-admin] allow to get ledger metadata along with topic stats-internal (#8180)
### Motivation
Pulsar-admin api and CLI utility is a tool used for operational and system debugging purpose. `pulsar-admin topics stats-internal` command gives internals of the topic and it also shows list of ledgers where data has been written. However, sometimes operation team wants to know more details about ledgers such as : number of ensembles and list of bookies which own the ledger to find out issue with faulty bookie. right now, we have to use zookeeper-shell utility and read znode value to fetch such information.
So, it would be useful if ledger-info also has ledger-metadata and we can get it from pulsar-admin CLI.
### Modification
- Added ledger metadata into ledger-info response of the `topics stats-internal` command.
- user can pass additional flag to add ledger metadata else user will not see any change in output of `topics stats-internal`
### Result
```
./bin/pulsar-admin persistent stats-internal <topic> -m
:
{
"ledgerId" : 23,
"entries" : 200,
"size" : 11100,
"offloaded" : false,
"metadata" : "LedgerMetadata{formatVersion=3, ensembleSize=2, writeQuorumSize=2, ackQuorumSize=2, state=CLOSED, length=11100, lastEntryId=199, digestType=CRC32C, password=OMITTED, ensembles={0=[1.1.1.1:3182, 2.2.2.2:3181], 100=[1.1.1.1:3182, 3.3.3.3:3181]}, customMetadata={component=base64:bWFuYWdlZC1sZWRnZXI=, pulsar/managed-ledger=base64:c2FtcGxlL3N0YW5kYWxvbmUvbnMxL3BlcnNpc3RlbnQvdDE=}}"
}
```1 file changed
