enhance(main/lesspipe): ship zsh completions

[TomJo2000]

lesspipe offers Zsh completions, these require zsh to be present on the host at build time though.

CC: @Biswa96

[Biswa96]

Could we consider the possibility of bypassing the zsh requirement? I would prefer to avoid adding unnecessary components to the host container.

[TomJo2000]

Yeah that's valid.
Unfortunately the --all-completions flag for configure doesn't bypass it.
(Could probably be considered a bug)

Adding a dummy zsh to $PATH didn't work in my testing either.
And I couldn't figure out what exactly would need patching in the configure script.
https://github.com/wofr06/lesspipe/blob/lesspipe/configure