feat: remove all systems'defaults and add a common default file

[WiemKhlifi]

What?

Integrate all system defaults and the system's logger defaults into a single defaults.yaml file.

Why?

This helps simplify the config's folder and avoids filling it with multiple default files for each new system.

How?

• Create one file containing all the common elements for all files and use it as default for all systems.
• Initialise the config based on this default file then add all the specific elements for each system from their system.yaml files as well as for the network.yaml file.

Note: There is another approach (shorter one) mentioned here and here.

[WiemKhlifi]

@sash-a I agree I don't like it either but we can avoid that if we only change the system name in the default before running the system.py file. I wouldn't say I like these two paths and the extra effort, but they're better than the old way.

So, based on what you said, I made a few changes based on that: add the num_updates, seed and total_timesteps to arch.yaml, and separate the logging params in the logging.yaml file.

But what remains unchanged is our use of different default configs for each system where the only difference is the system name (the network can be included as part of the default in the system.yaml`).

Thus, I made only one default for all systems and we only need to change the system name before running the system.py file OR just run this command and it will do the job:

python sytem_name.py system=system_name

[WiemKhlifi]

This will be taken care of after finishing our measure sets. An issue will be opened for this matter 😄