This PR makes a number of significant changes to the patching infrastructure:

1. This PR reorganizes the patching logic to be based on a more principled approach. Rather than maintaining lists of patch functions that are each responsible for filtering modules to apply themselves to, patches are organized in the patches directory in a tree structure matching dask itself. Patches are found and run by importing the same relative paths within the patches directory corresponding to a particular dask or distributed module.
2. It adds proper support for patching submodules. Previously the loader was being disabled whenever a real dask module was being imported, but this is problematic because if some dask modules import others they will pre-populate sys.modules with the real modules and therefore the loader will never be used for loading a patched version of the submodule.
3. Patches are no longer just functions applied to modules, they are arbitrary functions executed when a module is imported. As a result, a wider range of modifications is possible than was previously allowed. In particular:
4. The more general functions allow the entire module import to be hijacked and redirected to other modules.
5. The new framework is used to vendor a patched version of the accessor.py module in dask, which resolves the issues observed in Fix dask.dataframe import error for Python 3.11.9 dask/dask#11035.