Fuel resource

[amr-el-sayed]

• Tanks, Aircrafts, Missiles, etc can consume fuel as resource similar to the money logic.
• If all fuel got consumed, the player won't be able to move the units that require fuel to operate.
• Fuel can be acquired from oil derricks, or resources at sea, supply drop,
  or maybe a new generator like the ore generator etc.
• The fuel display will be added in the sidebar.