Add `tuono start` command

[Valerioageno]

Is your feature request related to a problem? Please describe.

Provide a way to serve production build using tuono CLI.

Note

In the future it might be used also to serve the dev build
See Allow dev build without server output.

Describe the solution you'd like

Proposed Steps:

1. On running tuono start, verify if the out folder exists.
2. If the out folder is missing, display an error message like: "Production build not found. Please run tuono build first."
3. If the folder exists, verify that all necessary files for the production build are present.
4. If everything is in order, run cargo run --release to start the server with optimized sources.

Describe alternatives you've considered

N/A

Additional context

• Enhancement: Implement .env file support for configuration management #570
• Add tuono start mention in the tutorial tuono-documentation#26

[NO7r34L]

@Valerioageno - It's me from Discord. Please assign this issue to me.