vm: replace vm-region with address-space

address-space is a non-recursive data structure, which contains a flat list of vm_areas representing
mapped vm-objects.

userspace programs can no longer create sub-address-spaces. instead, they can reserve portions of
the address space, and use that reserved space to create mappings.

vm/bootstrap.c

@@ -1,11 +1,12 @@
-#include <limits.h>
+#include <kernel/address-space.h>
 #include <kernel/machine/cpu.h>
 #include <kernel/memblock.h>
 #include <kernel/printk.h>
-#include <mango/status.h>
+#include <kernel/vm-controller.h>
 #include <kernel/vm-object.h>
-#include <kernel/vm-region.h>
 #include <kernel/vm.h>
+#include <limits.h>
+#include <mango/status.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ -42,7 +43,8 @@ kern_status_t vm_bootstrap(
 
 	kmalloc_init();
 	vm_object_type_init();
-	vm_region_type_init();
+	vm_controller_type_init();
+	address_space_type_init();
 	return KERN_OK;
 }