Saving catalog with overwrite should recreate the output directory

[camposandro]

Bug report

When saving a catalog to disk using to_hipscat the provided output path may have content (e.g. if previously a catalog was saved to that same directory). In this case we need to specify the overwrite flag to True.

However, the current behavior does not ensure that the output folder is erased and recreated. It only ensures that the previous catalog files that coincide with those of the new catalog are overwritten (parquet leaf files, as well as metadata). The parquet leaf files that do not directly match will the ones on the catalog currently being saved remain in that directory. The catalog saved to disk in this case is not correct.

We should throw an error alerting the user for the usage of the overwrite flag if it overwrite is False and the output directory has contents. If overwrite is True, the directory should be recreated from scratch.

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