Saving cubes with duplicated axes fails

tmp = YAXArray([CategoricalAxis("Cat", ["a", "b"]),
                CategoricalAxis("Cat", ["a", "b"])],
               rand(2, 2))

savecube(tmp, "data/tmp.zarr")

also fails when trying to save to a "nc" file. Duplicated axes are really useful for e.g. covariance matrices. A workaround is to just rename one of the axes to "Cat2" fails with the same error:

tmp = YAXArray([CategoricalAxis("Cat", ["a", "b"]),
                CategoricalAxis("Cat2", ["a", "b"])],
               rand(2, 2))

savecube(tmp, "data/tmp.zarr")

ERROR: Multiple possible axis matches found for YAXArrays.Cubes.Axes.ByName("Cat")

As a workaround the axis have to be named "Cat1" and "Cat2"

"Variable" also seems to be a forbidden substring, naming the axes "Variable1" and "Variable2" also fails, "Var1", "Var2" works.

Start by reproducing the examples through the savecube entry point with duplicated CategoricalAxis names, renamed axes, and both data/tmp.zarr and an nc file. Trace the axis-matching error, especially the ByName("Cat") and forbidden "Variable" cases. Done means cubes with duplicated or otherwise valid axis names save successfully without requiring Cat1/Cat2 or Var1/Var2 workarounds.