Model metadata should contain the trainer name

[sthaha]

Currently the trainer name is encoded in the name of the model's file while this allows for fast lookup, it prevents files to have different names (e.g. acpi_AbsPower.json) since the critical data is lost once renamed.

[sunya-ch]

Point to update:

kepler-model-server/src/kepler_model/train/trainer/__init__.py

Lines 245 to 246 in f8e611e

	if weight_dict is not None:
	save_weight(save_path, weight_dict)

[sunya-ch]

Currently, we add that only in model-server response here:

kepler-model-server/src/kepler_model/server/model_server.py

Lines 223 to 225 in f8e611e

	best_response["model_name"] = best_model["model_name"]
	if "machine_spec" in best_model:
	best_response["machine_spec"] = best_model["machine_spec"]

[sunya-ch]

can we close it by [kepler#1744](feat: get trainer from model_name in weight sustainable-computing-io/kepler#1744) ? @sthaha