REST Api call /v1/pool/batch/snapshots should work without parameters

[mutatrum]

The /v1/pool/batch/snapshots has two parameters, start_batch_id and num_batches_back. Without the parameters, the call doesn't work:
/v1/pool/batch/snapshots -> Not Found
/v1/pool/batch/snapshots/ -> Not Found
/v1/pool/batch/snapshots// -> JSON formatted error: type mismatch, parameter: num_batches_back
/v1/pool/batch/snapshots//1 -> Returns last batch snapshot.

This is a non-standard URL pattern. A more standard pattern would be to have num_batches_back as a query parameter and have the path parameter start_batch_id optional.

/v1/pool/batch/snapshots -> return array with last batch
/v1/pool/batch/snapshots/ -> return array with last batch
/v1/pool/batch/snapshots?num_batches_back=5 -> return array with last 5 batches
/v1/pool/batch/snapshots/deadbeef -> return array with batch deadbeef
/v1/pool/batch/snapshots/deadbeef?num_batches_back=5 -> return array with 5 batches starting from batch deadbeef

pool/poolrpc/trader.proto

Line 227 in 94db020

get: "/v1/pool/batch/snapshots/{start_batch_id}/{num_batches_back}"