dnf: upgrade 4.19.2 -> 4.20.0

Changelog:
==========
- Prepare man pages for switch to dnf5 as the default package manager
- Do not add user site-packages directory to sys.path
- Remove --duplicates and --oldinstallonly exit with 0 when nothing to remove
- repoquery: Fix loading filelists when -f is used
- Prepare for switch of dnf5 in Rawhide

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>