Switch to the 'fluido skin' for the site

Suggested by Benson.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Stop suggesting that we're an official Apache project

We are not, so let's not use their (trademarked) logo, as pointed out by
Benson Margulies.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add project information for use in the output of `mvn site`

The project information in the output of the maven-site-plugin is derived
from the project information provided in the pom.xml file. Therefore,
let's add some information for the benefit of having correct information
on our web site.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
The NAR plugin is not an Apache project

Therefore, it should not inherit from the Apache maven-parent project,
otherwise e.g. the output of `mvn site` will contain 'Maven projects'
and 'ASF' menus.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add an .svg version of the logo

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add a nice banner image for the upcoming new site

This banner is based on the NAR logo, of course.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Use the new banner in the output of `mvn site`

While at it, also clean up the links and the way the reports menu is
triggered.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>