Update examples/tutorials to NOT using retrofit agents

[dalonsoa]

Is your feature request related to a problem? Please describe

All examples and tutorials use the pair of agents newcapa/retorfit, but that is no longer necessary and MUSE works totally fine with just new capacity agents managing all the assets. However, this is not documented and no examples show how to use MUSE this way.

Describe the solution you'd like

Remove retrofit agents from all examples but 1 or 2.

Describe alternatives you've considered

Keep using retrofit agents. Retrofit agents might be useful but can be confusing, specially for new users, so better start with simpler scenarios.

Additional context

N/A