Split Agents to separate files

Request Summary

Currently, Agent list in scenario is very long and hard to navigate. Extract agents to separate files in a new subfolder agents. Split into these files:

Conventionals.yaml
Demand.yaml
MarketsAndForecast.yaml
RenewableAndPolicy.yaml
Storage.yaml

Use case

Easier to navigate scenarios.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information