reafactor(orbital): Reimplement Orbital support using std::fs and redox_event

[isan-Ethen]

Redox OS removed SYS_OPEN.
Therefore, calling raw syscall::open must be replaced with std::fs.
Also, event_socket should be implemented using redox_event.

• Tested on all platforms changed
• Added an entry to the changelog module if knowledge of this change could be valuable to users
• Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior
• Created or updated an example program if it would help users understand this functionality