feat: Add initial index lookup join operator implementation (#12218)

Summary:
Pull Request resolved: #12218

Add the initial index lookup operator implementation which supports inner join and left join
from an index source.
The index lookup join operator takes input from the probe side with one batch at a time. For each
probe input batch, it sends the lookup request from the index source and gets a lookup result iterator.
The result iterator produces the output in batches through a future for async processing at the
storage backend. For each lookup result, the index join operator produces one or more output batches
based on the operator's output batch size limit. For left join, the index join operator needs to detect the
input request rows that have no matches and produce output with nulls for the columns from the lookup
table.

Reviewed By: mbasmanova

Differential Revision: D68906030

fbshipit-source-id: 4038c31653bc96893497b3c26d935fa2f7b58f43

velox/exec/CMakeLists.txt

@@ -41,6 +41,7 @@ velox_add_library(
   HashPartitionFunction.cpp
   HashProbe.cpp
   HashTable.cpp
+  IndexLookupJoin.cpp
   JoinBridge.cpp
   Limit.cpp
   LocalPartition.cpp