Major refactor of codebase

include/drivers/ahci.h

@@ -0,0 +1 @@
+void ahci_init();

include/drivers/pmt.h

@@ -0,0 +1,3 @@
+#include <stdint.h>
+int pmt_init();
+void pmt_delay(uint64_t us);

include/drivers/serial.h

@@ -0,0 +1,8 @@
+#include <stdint.h>
+
+void serial_write(uint8_t data);
+uint8_t serial_read();
+
+void serial_print(char *str);
+
+void serial_init();