Add `turso tutorial` command and call it from Homebrew postinstall

[penberg]

Let's have a simple turso tutorial command that prints basic stuff like signup, login, etc, and make the Homebrew postinstall step call that instead.

[penberg]

@CodingDoug suggested that the command could just point people to the online tutorial, which is a great idea, but we want to also show the turso auth signup command at least, because that's what people need to run to get going.

[CodingDoug]

Yes, absolutely want to drive folks to sign up ASAP.

[CodingDoug]

The CLI tutorial can be found here, if the CLI wants to link to it:

https://docs.turso.tech/tutorials/get-started-turso-cli

[haaawk]

For homebrew part we just need to set post_install (https://goreleaser.com/customization/homebrew/?h=homebrew) in gorealeser config (https://github.com/chiselstrike/turso-cli/blob/main/.github/workflows/goreleaser.yml)

[StefanoSaffran]

It looks like it had already been done but it didn't work and it was reverted. https://github.com/chiselstrike/turso-cli/commit/a895b072bf4174b9484d20ab9e9eac0f49e69b07

[haaawk]

Please research what's the proper way to do it @StefanoSaffran

[haaawk]

Fixed with https://github.com/chiselstrike/turso-cli/pull/385