Reduce CLI time to action and fix convert-to-parquet help message

This is a short PR meant to reduce time spent waiting for CLI commands to initiate. Printing help messages could take over a minute due to very heavy submodules being loaded in the package's main __init__.py. These loads were removed temporarily until lazy loading can be implemented for very large dependencies such as cudf.

In addition the help message for convert-to-parquet was formatted incorrectly. The % characters are now correctly escaped