Piggyback migrator to drop {{ pin_compatible("numpy") }}

[jakirkham]

As numpy already contains a run_exports, which has been present since numpy version 1.22.3 number 1 ( conda-forge/numpy-feedstock#262 ), and conda-forge is using numpy version 1.22 or newer, we can just rely on run_exports from numpy and drop pin_compatible from recipes

This is also important to prepare for building with numpy version 2.0, which builds packages with numpy version 1.x and 2.x support. As such pin_compatible would be unnecessarily strict by restricting packages built with it to numpy version 2.x when 1.x could have also been supported

As a result (based on discussion at the core meeting), we decided to add a piggyback migrator that would remove {{ pin_compatible("numpy") }}. This would help prepare for the NumPy 2 migrator. It also could couple with that migrator to upgrade to NumPy 2 and clean this pinning out at the same time

[jakirkham]

cc @h-vetinari @isuruf @rgommers (please feel free to add or correct anything here)

[jakirkham]

cc @beckermr (for awareness)

[beckermr]

We need doc changes and possibly adjustments to the linter as well. Not sure if those were covered.

[jakirkham]

Please see issue: conda-forge/conda-forge.github.io#2156

Feel free to add anything else there

Edit: Didn't see a linter check for this, but please let me know if I missed it