Use new lxml_html_clean package when available.

[mauritsvanrees]

You need this when you are using lxml 5.2 or later. We don't want to make this a hard dependency.
When you use Plone 6.0.11 or later, you must use this new htmllaundry version. Fine for older Plone versions as well.

Note that in lxml 5.2 (or maybe all 5.x versions), the keyword arguments passed to a Cleaner must not be a string. So also our own link_target keyword argument must be a list. Changed the code accordingly.

[ale-rt]

I think this needs #3 to make at least the test pass.
I am not really sure we want anyway to continue maintaining this package.
I am not sure if the Python compatibility we claim makes sense.
Anyway I will approve the PR.

[mauritsvanrees]

The point would be to only do the changes in this one package, instead of in ploneintranet, euphorie, osha.oira, and any other packages where we use htmllaundry.

[ale-rt]

I would say let's get rid of this extra package.
We are working on a fork, it is not widely adopted and I think we could easily get rid of it in the future.