warning or some kind of status indication for DuckDB conversions into duckdb/parquet

[e-kotov]

Until progress bar is implemented for the R client for DuckDB (issue here duckdb/duckdb-r#199), provide some indication of how long the conversion might take. Without progress bar, the only way for the user to see the data conversion progress is to go to the output folder and update the file size of the duckdb file or folder with parquet files.

[e-kotov]

Kind of addressed for now with in the spod_convert():

message(glue::glue("Converting v{ver} {type} data for {zones} to {save_format}: {save_path} \n... This may take some time. You can see if the process is still running by going to the {save_dir} folder and refreshing the folder content and checking if the file/folder size of {basename(save_path)} is increasing after each refresh. The conversion speed depends on your processor speed, number of cores and the speed of your disk storage."))

This is the best we can do until progress bar is implemented in the {duckdb} for R duckdb/duckdb-r#199