Place ladders in the buildings

[SzatmariA]

Based on the given metric, buildings can be humongous. The stairs in the middle of the buildings are fine but hard to climb.
It would be beneficial to put ladders in or outside the buildings that could get the user up to the top of the building.

Steps to complete task:

• Define ladder in codemetropolis
• Link the same metric to the ladder as the height of the building
• Generate the ladders in the world