Move components into dedicated subdirectory

This brings us a lot more tidiness.

components/kernel_release.c

@@ -0,0 +1,17 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/utsname.h>
+#include <stdio.h>
+
+#include "../util.h"
+
+const char *
+kernel_release(void)
+{
+	struct utsname udata;
+
+	if (uname(&udata) < 0) {
+		return NULL;
+	}
+
+	return bprintf("%s", udata.release);
+}