LibArchive: Implement ZipOutputStream for zip archive creation

This output stream can be used to create zip archives, and will
be used in the implementation of the zip utility.

Userland/Libraries/LibArchive/Zip.h

@@ -31,6 +31,7 @@
 #include <AK/Span.h>
 #include <AK/Stream.h>
 #include <AK/String.h>
+#include <AK/Vector.h>
 #include <string.h>
 
 namespace Archive {
@@ -231,4 +232,17 @@ private:
     ReadonlyBytes m_input_data;
 };
 
+class ZipOutputStream {
+public:
+    ZipOutputStream(OutputStream&);
+    void add_member(const ZipMember&);
+    void finish();
+
+private:
+    OutputStream& m_stream;
+    Vector<ZipMember> m_members;
+
+    bool m_finished { false };
+};
+
 }