Separate grouping logic into reusable function

[ank1m]

Separate grouping logic for input arguments and corresponding batch indices into reusable python function for use in different Python modules, e.g. in harmony-autotester.
The grouping logic is repeated here:

batchee/batchee/tempo_filename_parser.py

Lines 143 to 150 in cb6246b

	batch_indices = get_batch_indices(input_filenames)
	unique_category_indices: list[int] = sorted(set(batch_indices), key=batch_indices.index)
	logging.info(f"batch_indices = {batch_indices}")
	# --- Construct a STAC object based on the batch indices ---
	grouped: dict[int, list[str]] = {}
	for k, v in zip(batch_indices, input_filenames, strict=False):
	grouped.setdefault(k, []).append(v)

and

batchee/batchee/harmony/service_adapter.py

Lines 103 to 105 in cb6246b

	grouped: dict[int, list[Item]] = {}
	for k, v in zip(batch_indices, items, strict=False):
	grouped.setdefault(k, []).append(v)

Replace the duplicated implementations in both locations with the reusable function and develop unit test for it.

[ank1m]

closed in #220