syscall: add remaining wasip1 files

syscall: add remaining wasip1 files

Implements filesystem, networking and os interactions.

For #58141

Co-authored-by: Richard Musiol <neelance@gmail.com>
Co-authored-by: Achille Roussel <achille.roussel@gmail.com>
Co-authored-by: Julien Fabre <ju.pryz@gmail.com>
Co-authored-by: Evan Phoenix <evan@phx.io>
Change-Id: If5c43ad5bd2955e6d2d4e2822fd68bce89ca786c
Reviewed-on: https://go-review.googlesource.com/c/go/+/479619
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>