*/*: switch dependency from devel/py-lxml5 to devel/py-lxml

Currently, there are two versions of python XML processing library
which conflict each other in the ports tree, namely:
- devel/py-lxml5 (now at version 5.4.0)
- devel/py-lxml  (now at version 6.0.1)

To avoid the situation that some ports depend on py-lxml5 and some
others do on py-lxml (by switching dependencies individually), this
commit switches the dependencies from py-lxml5 to py-lxml at once.

Additional note: There are still two ports (textproc/py-rdflib and
www/py-draftjs-exporter) depending on py-lxml5 since they limit upper
version to less than 6.

PR:		289491
Approved by:	Michiel van Baak Jansen <michiel@vanbaak.eu>, arrowd,
		crees, madpilot, delphij, marcus, nivit, kai,
		skreuzer, fluffy, bofh, thierry, stephen, sunpoet,
		0mp, Eric Camachat <eric@camachat.org>

devel/py-lxml-html-clean: enable testing (some tests fail though)

Approved by:	portmgr blanket

python: bump all USE_PYTHON=distutils consumers after RUN_DEPENDS removal

Any missed ports, feel free to bump.

Any ports that need setuptools at runtime can have the devel/py-setuptools
manually added back to RUN_DEPENDS, but understand that this practice
is deprecated; see CHANGES for details.

devel/py-lxml-html-clean: New port: HTML cleaner from lxml project

This project was initially a part of lxml. Because HTML cleaner is designed as
blocklist-based, many reports about possible security vulnerabilities were
filed for lxml and that make the project problematic for security-sensitive
environments. Therefore we decided to extract the problematic part to a
separate project.

Important: the HTML Cleaner in lxml_html_clean is not considered appropriate
for security sensitive environments. See e.g. bleach for an alternative.