Import, XTZ, pager, @rend, @rendition and <rendition> management

Transfert the rend attributes to the HTML elements (known or unknown)

Transfert the rendition@type=css elements as selectors in the CORPUS_TEXT.css

Note: rend attributes are already managed in TXM 0.8.3: rend and type (but not for the unknown elements)

see https://www.tei-c.org/release/doc/tei-p5-doc/fr/html/ref-att.global.rendition.html

(from redmine: issue id 3442, created on 2023/09/25 by Matthieu Decorde)