[cwconfig] Always use "sys.prefix" to determine installation prefix
We drop all legacy logic implemented in _find_prefix() which now happens
to be buggy since we cleaned up setup.py in 3.26 (noticeably because
virtualenv is no longer properly detected).
Closes #17132990.
Document: cubicweb-doc
Title: CubicWeb Documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/python-cubicweb-documentation/html/index.html
Files: /usr/share/doc/python-cubicweb-documentation/html/*