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

[MovGP0]

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:

# 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 on how a range of git commits can be specified
• See Git Diff and Patch and Git Format-Patch on details of git patch files