print integers and doubles

still need to add hex but i gtg so ill do that later

kernel/src/cstr.h

@@ -0,0 +1,6 @@
+#pragma once
+#include <stdint.h>
+
+const char* to_string(uint64_t value);
+const char* to_string(int64_t value);
+const char* to_string(double value, uint8_t decimalPlaces);