[kernel] Remove explicit allocator passing

Many kernel objects had to keep a hold of refrences to allocators in
order to pass them on down the call chain. Remove those explicit
refrences and use `operator new`, `operator delete`, and define new
`kalloc` and `kfree`.

Also remove `slab_allocator` and replace it with a new mixin for slab
allocation, `slab_allocated`, that overrides `operator new` and
`operator free` for its subclass.

Remove some no longer used related headers, `buddy_allocator.h` and
`address_manager.h`

Tags: memory

src/kernel/device_manager.cpp

@@ -60,12 +60,7 @@ void irq4_callback(void *)
 
 
 device_manager::device_manager(const void *root_table, kutil::allocator &alloc) :
-	m_lapic(nullptr),
-	m_ioapics(alloc),
-	m_pci(alloc),
-	m_devices(alloc),
-	m_irqs(alloc),
-	m_blockdevs(alloc)
+	m_lapic(nullptr)
 {
 	kassert(root_table != 0, "ACPI root table pointer is null.");