Currently, we do not support parsing encoded/compressed columns in file path, eg: extract column k1 from file path /path/to/dir/k1=1/xxx.csv
This patch is able to parse columns from file path like in Spark(Partition Discovery).
This patch parse partition columns at BrokerScanNode.java and save parsing result of each file path as a property of TBrokerRangeDesc, then the broker reader of BE can read the value of specified partition column.
