Scenario Configs

[abhiramm7]

Add metadata into scenario description so that users don't have to open yaml file or documentation to see the number of nodes being controlled. There are multiple ways this can be realized.

1. Doc string in class?
2. meta-data dict that can be read, kinda building on what I have already.

[abhiramm7]

Explains the reason why we use __<var name> for defining internal variables: https://medium.com/python-features/naming-conventions-with-underscores-in-python-791251ac7097.

Add it to documentation.