LibGfx: Add initial ISO BMFF parsing and a utility to print file info

Currently, the `isobmff` utility will only print the media file type
info from the FileTypeBox (major brand and compatible brands), as well
as the names and sizes of top-level boxes.

Userland/Libraries/LibGfx/ImageFormats/ISOBMFF/BoxStream.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2023, Gregory Bertilson <Zaggy1024@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Stream.h>
+
+namespace Gfx::ISOBMFF {
+
+class BoxStream final : public Stream {
+public:
+    explicit BoxStream(Stream& stream, size_t size)
+        : m_stream(stream)
+        , m_data_left(size)
+    {
+    }
+
+    virtual bool is_eof() const override { return m_stream.is_eof() || remaining() == 0; }
+    virtual bool is_open() const override { return m_stream.is_open(); }
+    virtual void close() override { m_stream.close(); }
+    virtual ErrorOr<Bytes> read_some(Bytes bytes) override
+    {
+        auto read_bytes = TRY(m_stream.read_some(bytes));
+        m_data_left -= min(read_bytes.size(), m_data_left);
+        return read_bytes;
+    }
+
+    virtual ErrorOr<size_t> write_some(ReadonlyBytes) override { VERIFY_NOT_REACHED(); }
+    virtual ErrorOr<void> write_until_depleted(ReadonlyBytes) override { VERIFY_NOT_REACHED(); }
+
+    size_t remaining() const
+    {
+        return m_data_left;
+    }
+    ErrorOr<void> discard_remaining()
+    {
+        return discard(remaining());
+    }
+
+private:
+    Stream& m_stream;
+    size_t m_data_left;
+};
+
+}