parquetAnalyzeForeignTable does not set totalpages

[sdressler]

The function parquetAnalyzeForeignTable does not assign a value to totalpages. This is however needed for estimation (most notably in parquetGetForeignRelSize).

Proposed implementation (pseudocode):

total_byte_size = 0;
foreach pq_file in files do
  total_byte_size += SumRowGroupSizes(pq_file);
end
*totalpages = total_byte_size / BLCKSZ;