Feat zarr reader (#298)

* feat: zarr reader

* doc: improved graph_util documentation

* refactor: simplified fragments graph class

* minor upd

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Co-authored-by: anna-grim <anna.grim@alleninstitute.org>

Author: anna-grim

src/deep_neurographs/inference.py

@@ -587,7 +587,7 @@ def run(self, fragments_graph, proposals):
                     fragments_graph.merge_proposal(p)
                     accepts.append(p)
                 pbar.update(len(batch["proposals"]))
-            fragments_graph.absorb_reducibles()
+            #fragments_graph.absorb_reducibles() - extremely slow
         return fragments_graph, accepts
 
     def get_batch(self, fragments_graph, proposals, flagged_proposals):