Add Knn UDF to ydbd (#2871)

Author: azevaykin

ydb/apps/ydbd/ya.make

@@ -48,6 +48,7 @@ PEERDIR(
     ydb/library/yql/udfs/common/histogram
     ydb/library/yql/udfs/common/hyperloglog
     ydb/library/yql/udfs/common/ip_base
+    ydb/library/yql/udfs/common/knn
     ydb/library/yql/udfs/common/json
     ydb/library/yql/udfs/common/json2
     ydb/library/yql/udfs/common/math