Add modularity for setting config.yml file

[Dynnammo]

When launching the script, it launches the file called config.yml by default.

As we begin to use this production, its troublesome and mistake-triggering to rewrite this file between launching the update script.

Solution : having an input question that asks for the file wanted. As instance, if I create a file called config-berlin.yml for the Berlin city, I will have the possibility to launch it whenever I want.

Solution 2 : having a more abstract config-global.yml that holds all wanted updatable cities, we would just have to fill it with cities we want to upgrade their models.

Solution 3 : up to whatever I may have not think of

[Dynnammo]

Solved in #27