Add a section to point to the other portals same as Supported by and with the collaboration of.

[Bilelkihal]

Context

Agroportal is an instance of the Ontoportal technology, distributed and maintained by the Ontoportal alliance members, for today we count the following Ontoportal instances, in addition to Agroportal: Bioportal, Bioportal SIFR, EarthPortal, Ecoportal, BioDivportal, Indsutryportal, MedPortal, and Matportal. (see the ontoportal website https://ontoportal.org for an updated list)

Goal

A good thing to have is that on each portal, on the homepage a section, lists all the Ontoportal instances, with logos and links to them.

This will help people find them more easily, and be the first brick of a federation system in the future.

Requirements

• Be configurable, and defined in the configs files of the portal
• Be a section in the homepage, that have the logos and links to the portals
• When clicked open a new tab to the portal

[syphax-bouazzouni]

Done in #524