Fixes #2429

Description

This patch (in progress) is rewriting Scholia to make various server-side details (e.g. SPARQL endpoint) configurable with a properties file.

Caveats

• This change requires a documentation update
  • I have made corresponding changes to the documentation
• This change requires new dependencies: configparser, StringIO, os.path

If you make changes to the Python code

• My code passes the tox check, I can receive warnings about tests, documentation or both

Testing

The patch defaults use the WDQS and with the following scholia.cfg it will use the QLever Wikidata endpoint:

to be done

Checklist

• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have not used code from external sources without attribution
• I have considered accessibility in my implementation
• There are no remaining debug statements (print, console.log, ...)