new feature: `config` subcommand to manage configuration (interactively)

### Feature Description

like `git config`, providing a built-in subcommand to help add, view, edit or remove configurations. With a minimal but friendly TUI

### Problem and Solution

For example, `oli config add` will prompt the user to fill in the storage type, endpoint, etc., to help them get started quickly without needing to find and read our documentation.

### Additional Context

_No response_

### Are you willing to contribute to the development of this feature?

- [x] Yes, I am willing to contribute to the development of this feature.

No file, test, or entry point is named. Start by locating the Rust CLI command definitions and existing configuration handling, then review how storage type and endpoint are represented. Done should include an interactive `oli config` subcommand supporting add, view, edit, and remove with a minimal friendly TUI.

Written by the indexing model from the issue text.