feat: gnoverse, a sandbox system around gnovm

[moul]

WIP

EDIT: change of plan, I'll try to improve gno.land/pkg/gnoland before creating a new gnovm/pkg/gnoverse.

Introducing gnoverse: A versatile sandbox environment for managing multiple users and their states within the 'gnovm.' Create mock Gno machines for testing or build blockchain-less multi-user Gno servers like HTTP APIs, SSH servers, and more. Explore the Gno universe with gnoverse! 🚀

Blocks #979
Addresses gnolang/hackerspace#23
Addresses #972
Related with gnolang/hackerspace#15
Addresses gnolang/hackerspace#16

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[Kouteki]

Note: 'gnoverse' name has been assigned to the community org: https://github.com/gnoverse

If we move forward we'd need another name to avoid confusion.