[boot] Load programs in boot, not kernel

Remove ELF and initrd loading from the kernel. The bootloader now loads
the initial programs, as it does with the kernel. Other files that were
in the initrd are now on the ESP, and non-program files are just passed
as modules.

src/boot/paging.h

@@ -39,13 +39,11 @@ void allocate_tables(
 void add_current_mappings(page_table *new_pml4);
 
 /// Map a physical address to a virtual address in the given page tables.
-/// \arg pml4  The root of the set of page tables to be updated
-/// \arg args  The kernel args header, used for the page table cache
+/// \arg args  The kernel args header, used for the page table cache and pml4
 /// \arg phys  The phyiscal address to map in
 /// \arg virt  The virtual address to map in
 /// \arg size  The size in bytes of the mapping 
 void map_pages(
-	page_table *pml4,
 	kernel::args::header *args,
 	uintptr_t phys, uintptr_t virt,
 	size_t bytes);