Adding a bottom area on front page for 'our partners' promotion

On codabench, there is not yet a place to promote big project partners like there is on Codalab: https://codalab.lisn.upsaclay.fr/highlights, at the page bottom. The logos recently added in the top banner are targeting the instance providers of a given instance, and can be customized. We need another place, which is not customizable, to display these other logos. This can be done below the citation note on the front page.