Improve gno run

[moul]

The gno run command is presently in a pre-alpha phase and may not perform reliably due to its specific requirements for package and function naming.

Its primary objective is to facilitate a smooth transition for developers from Go by allowing them to start with a basic main function. Additionally, it aims to provide utility tools for those who are forking or reviewing a package.

To enhance its usability and commence documentation in guides, two primary enhancements are urgently needed:

1. The inclusion of argument passing support akin to os.Args, enabling more dynamic results from a single main function based on various parameters.
2. Increased flexibility in the package PKGPATH specification, making it easier to add a main function and execute gno run on a package without having to specify a file (related to issue Allow *_test.gno file to run pkg with _test as suffix #768).

Addresses #972

[ajnavarro]

Starting with the implementation of the first enhancement (os.Args).

[ajnavarro]

I refactored the RunMain() method to accept a slice of arguments. Apart from that, I added the os package into the stdlibs gnovm folder.

stdlib is loaded when using VMKeeper but RunMain() is on the Machine struct, so it looks a bit strange that to make Args work, you need to use the VM through the VMKeeper.

I'm having some problems injecting the Args into a var inside a package, waiting for #859 which should make the process simpler.

If someone has some insights about how to move forward, I'd be willing to chat with you about it.

[moul]

Do you already have a PR for your work? can you share, the link?

[ajnavarro]

@moul I don't. Because I wasn't able to make it work, I just discarded the changes. I can recreate and add them to a draft PR.

[moul]

Yes please, a draft PR may be useful to help you.

[ajnavarro]

@moul This is what I was trying to do: #982