Switch to slab allocator

[Andy-Python-Programmer]

Currently the aero_kernel uses the linked_list_allocator crate for the kernel allocator. We might want to switch the allocator from a linked list allocator to an object-caching slab allocator which is more efficient.

The basic idea behind the slab allocator is to have caches of commonly used objects kept in an initialised state available for use by the kernel. Without an object based allocator, the kernel will spend much of its time allocating, initialising and freeing the same object. The slab allocator aims to to cache the freed object so that the basic structure is preserved between uses.

cc https://www.kernel.org/doc/gorman/html/understand/understand011.html
cc https://people.eecs.berkeley.edu/~kubitron/courses/cs194-24-S13/hand-outs/bonwick_slab.pdf

[Zildj1an]

A look at this may help.