Record networking and DMA development progress

Add the current OS source tree, build scripts, system image layout, and development notes covering DMA page allocation, e1000 bring-up, net API dispatch, and DHCP work in progress.

CODE/UTSM/arch/x86_64/io.c

@@ -0,0 +1,15 @@
+#include <utsm/types.h>
+
+void outb(u16 port, u8 value) {
+    __asm__ volatile ("outb %0, %1" : : "a"(value), "Nd"(port));
+}
+
+u8 inb(u16 port) {
+    u8 value;
+    __asm__ volatile ("inb %1, %0" : "=a"(value) : "Nd"(port));
+    return value;
+}
+
+void io_wait(void) {
+    outb(0x80, 0);
+}