Add shell completions for bash/zsh/fish/posh/etc

### Description of the problem

```
❯ gitmoji -
option
-c Interactively commit using the prompts
--commit Interactively commit using the prompts
--config Setup gitmoji-cli preferences.
-g Setup gitmoji-cli preferences.
-i Initialize gitmoji as a commit hook
--init Initialize gitmoji as a commit hook
--list List all the available gitmojis
...
```

### Solution

I guess in javascript there exists a library to generate shell completions automatically like

-
-
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### Alternatives

Don't use any library, like or ?

### Additional context

_No response_

### Validations

- [X] Follow our [Code of Conduct](https://github.com/carloscuesta/gitmoji-cli/blob/master/CODE_OF_CONDUCT.md)
- [X] Read the [Contributing Guide](https://github.com/carloscuesta/gitmoji-cli/blob/master/.github/CONTRIBUTING.md).
- [X] Check that there isn't already an issue requesting the same feature.

The issue names no files, tests, or entry points. Start by locating the CLI option definitions and reviewing the suggested completion libraries and existing completion-script examples; done means gitmoji exposes useful completions for the requested shells without breaking current options.

Written by the indexing model from the issue text.