Draft: Add `storage_mode` Attribute Support to MaxPooling

Context

This merge request introduces support for the storage_mode attribute in the MaxPooling operator.

The storage_mode flag determines the layout of the returned indices:

• storage_mode = false (default): row-major (C-style) indexing
• storage_mode = true: column-major (Fortran-style) indexing

This enhancement provides greater flexibility in how MaxPooling indices are represented, which is particularly useful for interoperability with external frameworks or when custom indexing schemes are required.

Note: Existing behavior remains unchanged when storage_mode is not specified (default is false).

Fixes aidge_core#323