Feature: Range queries

[stevefan1999-personal]

Description

Support range queries like TiKV: https://tikv.org/docs/dev/develop/rawkv/scan/

client.put(ByteString.copyFromUtf8("k1"), ByteString.copyFromUtf8("v1"));
client.put(ByteString.copyFromUtf8("k2"), ByteString.copyFromUtf8("v2"));
client.put(ByteString.copyFromUtf8("k3"), ByteString.copyFromUtf8("v3"));
client.put(ByteString.copyFromUtf8("k4"), ByteString.copyFromUtf8("v4"));

// scan with limit
int limit = 1000;
List<Kvrpcpb.KvPair> list = client.scan(ByteString.copyFromUtf8("k1"), ByteString.copyFromUtf8("k5"), limit);
for(Kvrpcpb.KvPair pair : list) {
    System.out.println(pair);
}