search: keep selected tab based on URL

* togglable button in Literature bucket

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
templates: better style for search tabs

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
templates: small tweaks on the front page

* added text after logo
* different style for news box

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>
templates: drop header tagline

Signed-off-by: Georgios Kokosioulis <georgios.kokosioulis@cern.ch>