Select base dataset for merging datasets with same Fingerprint.

Datasets with same Fingerprint have to be merged into one.

Selecting the "base" dataset should be based on the guidelines given by the DCAT-AP.de manual, e.g. the dataset with the most up-to-date modification date has to be be selected. This is in reality complicated as many datasets do not carry a modification date or all sources provide the same, in which case it cannot be used for selection.

After analysis of the data, this MR proposes a ranking of dataset sources to be considered in the selection process.

Also, this MR implements some Rust-Fu to optimize hardware access when de-duplicating datasets.