Removing unused dependencies (fixes issue #4873)

[thinrope]

One line description of pull request

Removing unused dependencies (fixes issue #4873)

Description:

While working on packaging latest plaso for Gentoo, I found three python modules (idna, cryptography, cffi) which are not referenced in any code, yet they are installed by some of the scripts. Related issue: fixes #4873

Checklist:

• [x] Automated checks (GitHub Actions, AppVeyor) pass
• [x] No new new dependencies are required or l2tdevtools has been updated
• [x] Reviewer assigned