Consider separating as-cell-summaries by laterality

[andreasbueckle]

Relevant for kidney, ovary, eye, knee, and others.

[bherr2]

If we end up slicing by scenegraph node, laterality would be taken car of as part of that (the laterality is part of the node's name)

[andreasbueckle]

For indexing/querying purposes, would it be better to have an additional, explicit field with the laterality? Might be hard to find/parse if it is embedded in a string.

PS: This issue is related to #96

[bherr2]

Maybe, but you should be able to do a graph query to go from the scenegraph node (which could be the URI of the Spatial Entity) and then get the laterality from the reference organ it's part of.