Reorganize rule matching

[J08nY]

Fixes #227.

This reorganizes the rule matching of both CC and FIPS in the following way:

• Rules are no longer in a Python file but in a YAML file.
• Rules have more than one level of categorization, for example the cc_cert_id rule has subcategories for each country issuing certificates and that subcategory has at least one but potentially more rules. This tree-like structure is passed on to the results of rule matching and is intentionally not flattened in the process.
• The rule matching code is unified between FIPS and CC, and simplified somewhat.
• The huge helpers module is split in several modules in the utils subpackage.

Overall, removing the effects of the Python -> YAML conversion and test dataset update (added many new lines), this change should be a net negative on the code size.

I suggest to squash this during merge, as the commits are not particularly of high quality.

[J08nY]

The to_pandas serialization is unchanged as the pandas tuple is based on heuristics and those are all working with the new rule setup.