[kernel] Make capabilities/handles global

Instead of handles / capabilities having numeric ids that are only valid
for the owning process, they are now global in a system capabilities
table. This will allow for specifying capabilities in IPC that doesn't
need to be kernel-controlled.

Processes will still need to be granted access to given capabilities,
but that can become a simpler system call than the current method of
sending them through mailbox messages (and worse, having to translate
every one into a new capability like was the case before). In order to
track which handles a process has access to, a new node_set based on
node_map allows for an efficient storage and lookup of handles.

definitions/memory_layout.yaml

@@ -13,6 +13,12 @@
 - name: heap
   size: 32G
 
+- name: capsmap
+  size: 32G
+
+- name: caps
+  size: 32G
+
 - name: stacks
   size: 64G