cleanup API for methods changing/dropping Array labels/values vs labels in Axis/AxisCollection #783

Functions to change labels and values are inconsistent for LArray, Axis and AxisCollection.

e.g. Array.set_labels can accept both a mapping and functions, but the same functionality is split in two functions for values: apply and apply_map; the functions do not have cohesive names, etc.

Array.apply_map and Axis.replace/Array.set_labels/AxisCollection.set_labels

All these functions provide some way to replace some values by some other values on their respective level. We should:

1. find cohesive names for the functions. For examples:

   • Array.replace_labels, Array.replace_values, Axis.replace_labels, AxisCollection.replace_labels
     or

   • Array.change_labels, Array.change_values, Axis.change_labels, AxisCollection.change_labels
     or

   • Array.set_labels, Array.set_values, Axis.set_labels, AxisCollection.set_labels,
     (Array.replace_values/change_values/set_values) would replace both Array.apply and Array.apply_map

   • Array.drop_labels, Array.drop_values, Axis.drop_labels, AxisCollection.drop_labels

   • Array.sort_labels, Array.sort_values, Axis.sort_labels, AxisCollection.sort_labels

   • Array.insert, Axis.insert, AxisCollection.insert_labels, AxisCollection.insert_axes
     or

   • Array.insert_labels??? (inserts both labels & values), Axis.insert_labels, AxisCollection.insert_labels

   • Array.append (appends both label & value), Axis.append, AxisCollection.append_labels, AxisCollection.append_axis

   • Array.combine_axes, Array.split_axes
     or

   • Array.combine_axes, Array.split_labels, Array.chunks, Axis.chunks (see implement Axis.chunks & LArray.chunks #505)

2. make sure the arguments & functionality are as close as possible.