Javadoc use same header than web site

[HydrolienF]

For updating javadoc we need :

• [x] download web site header page https://formiko.fr/en/header.html
• [x] add it as header of javadoc

[HydrolienF]

It don't use exactly the same header, because it don't have translation list.

[HydrolienF]

Some style change have been done so that header look like exactly the same on every web site pages (including javadoc ones)