Improve help message response for CLI

This merge request moves import of large modules into the main functions of the CLI scripts after input arguments have been parsed. This is to avoid having to wait until a large module is loaded in order to print a help message. This does not affect the runtime of the commands themselves.

Additionally, the hive conversion logic has been moved into its own script. Group determination for hive conversion has also been moved from the CLI script into this new ./policy/hive.py file.

src/rc_gpfs/cli/__init__.py

-from .convert_flat_to_hive import convert_flat_to_hive
-from .convert_to_parquet import convert_to_parquet
-from .split_log import split_log
-from .fparq_cli import fparq_cli
\ No newline at end of file
+#from .convert_flat_to_hive import convert_flat_to_hive
+#from .convert_to_parquet import convert_to_parquet
+#from .split_log import split_log
+#from .fparq_cli import fparq_cli
\ No newline at end of file