Moved layout to general-theme (do it once)
Added help-site-templates for multi-theme
Modified german-help-sites with bootstrap3 classes
Adapted english help-pages to bootstrap 3 layout
Adapted french help-pages to bootstrap 3 layout
Adapted italian help-pages to bootstrap 3 layout
Added missing classes for images
Add footer links by theme
Merge branch 'feature/3287_103_Help_pages_swissbib_multi' into development