Query Groups Join

Runs several single-group queries and merges them on shared, aligned dimensions.

Each entry in queries is a standard load query for a single query group. Each entry in align is a positional list of dimensions to align (cols[i] is the dimension of queries[i], or None if that query lacks the axis); the results are full-outer joined on the aligned dimension tuples. The dimensions in an align entry must share one declared align_axis, and that axis names the resulting output column.