refactor(cli): merge argument parsing and command execution

[SuperFluffy]

Summary

Refactors the CLI to give it a cleaner structure.

Background

The CLI was split into a cli module that was concerned with parsing arguments, and a commands which consumed the argument data structures.

The patch clears this up by implementing inherent <Args>::run methods on all leaf argument types, so that the implementation follows the same structure for all its effects.

Note that this match does restructure the public facing command line (except for a few lines of documentation). It merely restructures the implementation.

Changes

• Refactors each type deriving clap::Args to have an inherent method run.
• Flattens the crate structure to not be unnecessarily nested.

Testing

These will be tested in follow PRs. Smoke tests using a subset of the astria CLI commands should still work.

Related Issues

Closes #1546