[enhance] bsl: binded File.exists
[fix] stdlib/file: improve and add bindings
[feature] stdlib: Added new beta Socket module.
This module is intended to provide some low-level networking if you
don't want the burden that comes with Hlnet.
Please be aware that this module is still experimental.
[enhance] stdlib.io: Moved the File module.
The File module is now located inside the stdlib.io.file package.
[doc] review: Review of stdlib.io
Initial open-source release