[Feature/SSH] Copy functionality is not implemented

[koNinja]

Summary

The implementation of SFTP filesystem operations corresponding to std::filesystem are not fully implemented.
They will be implemented with reference to: https://en.cppreference.com/w/cpp/filesystem.html

Not implemented

• Recursive directory iterators
• Copy
• Recursive deletion
• Support for symbolic links

etc

Source

• https://github.com/koNinja/linuxplorer/tree/d6448723179f1a0244212534eb9b97eeb68d9798/include/ssh/sftp/filesystem