Add conservation analysis page

Add one (or more) new page(s) to perform conservation/comparative analysis of sequences.

• Name of the page/route : "Alignement", "Comparative", "Conservation" …?

See https://nextcloud.inrae.fr/apps/onlyoffice/147725794?filePath=%2Fmetribo%2FComparativeAnalysisOnTargetAlignment.doc for more infos