Kernel: Make RAMFS pass along the inode type when traversing as a dir

RAMFS was passing 0, which lead to the userspace seeing all entries as
DT_UNKNOWN when iterating over the directory contents.
To repro prior to this commit, simply check `echo /tmp/*/`.

Kernel/FileSystem/RAMFS/FileSystem.h

@@ -27,6 +27,19 @@ public:
 
     virtual Inode& root_inode() override;
 
+    virtual u8 internal_file_type_to_directory_entry_type(DirectoryEntryView const& entry) const override;
+
+    enum class FileType : u8 {
+        Directory,
+        Character,
+        Block,
+        Regular,
+        FIFO,
+        Link,
+        Socket,
+        Unknown,
+    };
+
 private:
     RAMFS();