Add some basic code, build kernel stuff in tree

sw/test_code/fs_test/main.c

@@ -1,8 +1,11 @@
 #include <stdio.h>
+#include <filesystems/fat32.h>
 
 void fat32_init(void);
 
 int main(void) {
+    struct fat32_directory_entry dentry;
     fat32_init();
+    fat32_get_cluster_by_name("KERNEL  O65", &dentry);
     return 0;
 }