[multiqc] Add link to Help4multiqc

Find a way to add this text at the top of the report :

You can find detailed guidance on how to interpret the following graphs in the Help4MultiQC GitBook (#https://bios4biol.pages.mia.inra.fr/Help4MultiQC/). Developed by some members of the CATI Bios4Biol team at INRAE, this resource provides valuable insights into data interpretation. While it was not specifically created for this report, it offers complementary information that may help deepen your understanding of the presented data.

Claire Hoede is OK to do that