Add link to polito-materiale repo

[e-caste]

• [x] English text: @e-caste
• [x] Italian text: @e-caste
• [ ] Chinese text: @itIsJim
• [x] Farsi text: @hesam1993
• [x] icon (light+dark): @stefaniabertilone

[itIsJim]

the new revision has been pushed to branch: Jim