Make number of tables in LoadTableStatistics configurable

[albertospelta]

We should consider making the current hard-coded value of 50 in the LoadTableStatistics method configurable by introducing a tableBatchSize parameter. This enhancement is similar to the columnBatchSize parameter that was added to the LoadColumnStatistics method in #131

Originally posted by @corycundy in #131 (comment)

One other observation that I made is that similar logic is used in the LoadTableStatistics method where 50 is hard coded. var loopTables = tableList.SplitList(50);