Add ability to inspect specific commits and diffs via command line arguments

**Is your feature request related to a problem? Please describe.**

It should be easily possible to inspect the changes by a given git commit/patch or range of commits.

**Describe the solution you'd like**

There should be command line arguments to show the git commits.

*Examples:*
```shell
# inspect a specific git commit
gitui --commit COMMITHASH

# inspect a range of commits
gitui --commit REV1..REV2

# inspect a range of commits and skip the first one
gitui --commit REV1^..REV2

# inspect from a given commit to HEAD
gitui --commit REV1..HEAD
gitui --commit REV1..

# inspect a git patch file
gitui --inspect SOMEFILENAME.patch
```

**Describe alternatives you've considered**

There should be a method via the CLI UI for selecting a range of commits or a patch file for inspection.

**Additional context**

- See [Git Revision](https://git-scm.com/docs/gitrevisions) on how a range of git commits can be specified
- See [Git Diff and Patch](https://www.freecodecamp.org/news/git-diff-and-patch/) and [Git Format-Patch](https://git-scm.com/docs/git-format-patch) on details of git patch files

Commencez par localiser l’analyse des arguments de ligne de commande de gitui et les points d’entrée existants pour l’inspection des commits ou des diffs. Vérifiez comment les exemples utilisant --commit et --inspect doivent correspondre à des plages de révisions Git et à des fichiers de patch. C’est terminé lorsque les arguments demandés fonctionnent pour les cas listés de commit, de plage, de HEAD et de fichier de patch.

Rédigé par le modèle d'indexation à partir du texte de l'issue.