create the file set needed by jlesage/docker-firefox

[strunzoz]

Is your feature request related to a problem? Please describe.
I am not savvy enough to sort out this chaining issue myself

Describe the solution you'd like
Generate the TWO files I need for https://github.com/jlesage/docker-firefox?tab=readme-ov-file#certificates

Describe alternatives you've considered
I have a ticket there explaining the permutation I had tried.

Additional context
I must be missing something extremely obvious