feat: add ricochet item toml command

[JosiahParry]

This PR adds a ricochet item subcommand with the first command being toml.

[JosiahParry]

@pat-s review when you can! One point of friction right now with the cli is that we cannot update settings from it yet.

The idea here is that we can fetch the current remote settings as a _ricochet.toml and update it locally. This would be the first step of just fetching the toml to maintain synchronicity locally and remotely.

[pat-s]

This "sounds" wrong to me reading-wise, i.e. item as the subcommand and then a format as the key for it.

Something like the following feels more "common":

• ricochet content <id> --config
• ricochet app <id> --config

Rationale: without --config, an overview of the content/app is returned. --config returns specifically` the TOML config. It's always TOML, so no need to specify that one explicitly.

The API endpoint is also named content, so sticking to similar naming as we already have likely makes sense overall.

[JosiahParry]

Heard. My thinking is that we should be able to collect content item commands under a subcommand like:

• ricochet content invoke (id inferred from local _ricochet.toml)
• ricochet content schedule to call /schedule endpoint
• ricochet content update-settings (or better name)
• ricochet content deployments

Then we would be able to have other grouped API endpoints as subcommands like admin and user