This pull request adds annotations for all remaining ndarray / generic non-magic methods.

Fortunately, most of these methods were already typed in their function-based counterpart from
np.core.fromnumeric, so they could be copied over with minor alterations.

A few notes and observations:

• The annotations are mostly geared towards ndarray. While they're not necessarily incorrect for
  generic, the signatures are generally speaking a bit too broad. Something to refine in a follow up.

• The overload pattern of ndarray.all() is a very common one here:

  • out is None, axis is None and keepdims is False -> a generic is returned.
  • out is None and (axis is not None or keepdims is True) -> a generic or ndarray is returned.
  • out is not None -> out is returned. One of the few cases where we can safelly use a typevar.

• A few annotations, that were recently moved to np.core.fromnumeric (MAINT: Move the fromnumeric annotations to their own stub file #17309), have been
  moved back to the main __init__.pyi file, as they were needed for the newly annotated methods.

• A number of methods, that are either just plain unavailable to generic or require a >=1D array, have
  been moved from _ArrayOrScalarCommon to ndarray.