Replace docserv-create-archive with Python code

[tomschr]

Situation

The scriptdocserv-create-archive is a separate script and is called inside Docserv. It creates ZIP archives with all files in specified formats from a given directory.

This design has some issues:

• It's inefficient as the internal state needs to be passed to the script (that's why it takes many options)
• Bash is slower than pure Python code

Proposed solution

• Integrate the functionality into Docserv code as Python.
• If really needed, provide a Python script that calls the internal code.