QR for non-tall-skinny matrices and split=0

[mrfh92]

Feature functionality
what the title tells

Additional context
required for everything that depends on QR

[github-actions]

Branch features/1736-QR_for_non-tall-skinny_matrices_and_split=0 created!

[github-actions]

This issue is stale because it has been open for 60 days with no activity.