Add drone imagery for each city where available

[enockseth]

• [ ] Abidjan
• [x] Accra
• [x] Kampala
• [ ] Kinshasa
• [ ] Monrovia
• [x] Ngaoundere
• [ ] Pointe-Noire
• [ ] Saint-Louis
• [ ] Seychelles
• [ ] Yaoundé
• [ ] Zanzibar