Add -ignore option to plakar ptar

[mdaeron]

Is your feature request related to a problem? Please describe. I would like to create from scratch a ptar archive of a list of dirs, but excluding files/patterns such as .git, .venv, etc.

Describe the solution you'd like I'd like to use something like plakar ptar -ignore .venv -ignore .git -o out.ptar /path/to/input/dir. Adding -ignore-file as well would be great.