Pre-made aggregates consistency will fail if less data / files are pulled

In case less files are regenerated / pulled from one month, there will be a leftover from the previous version's data.

Aggregate download should then remove and recreate the output folder.

Desired behaviour:

• By default the program should exit if out folder exists (we don't want to ruin user space).
• Add an option to override the folder deletion.
• Delete the folder if existing and replace it with new data.

We leave for the next releases the local check to minimise data transfer as:

1. Currently the data transfer is small (less than a daily dump file).
2. The logic to retrieve sha1 is slightly different w.r.t. the dumps (we did not encode yet the file name urls in the logic).