fix: upgrade from LegacyVersion

[terriko]

Restarting the effort to handle the cases that were previously handled by LegacyVersion so we can upgrade to the latest packaging. This doens't actually work yet.

[terriko]

Currently failing 12 tests:

 =========================== short test summary info ============================
FAILED test/test_csv2cve.py::TestCSV2CVE::test_csv2cve_valid_file - assert 52 >= 60
FAILED test/test_cvescanner.py::TestCVEScanner::test_canonical_convert[product0-2.11.1-] - TypeError: cannot unpack non-iterable Version object
FAILED test/test_cvescanner.py::TestCVEScanner::test_canonical_convert[product1-2.11.1-] - TypeError: cannot unpack non-iterable Version object
FAILED test/test_cvescanner.py::TestCVEScanner::test_canonical_convert[product2-1.1.0h-1.1.0.7] - packaging.version.InvalidVersion: Invalid version: '110h'
FAILED test/test_cvescanner.py::TestCVEScanner::test_canonical_convert[product3-1.1.0h-1.1.0.7] - packaging.version.InvalidVersion: Invalid version: '110h'
FAILED test/test_cvescanner.py::TestCVEScanner::test_canonical_convert[product4--] - packaging.version.InvalidVersion: Invalid version: ''
FAILED test/test_cvescanner.py::TestCVEScanner::test_canonical_convert[product5-7.4-] - TypeError: cannot unpack non-iterable Version object
FAILED test/test_cvescanner.py::TestCVEScanner::test_canonical_convert[product6-7.4-] - TypeError: cannot unpack non-iterable Version object
FAILED test/test_exploits.py::TestExploitScanner::test_exploit_checker[True-exploits_list0-product_info0-triage_info0-CRITICAL-EXPLOIT] - IndexError: list index out of range
FAILED test/test_exploits.py::TestExploitScanner::test_exploit_checker[False-exploits_list1-product_info1-triage_info1-CRITICAL] - IndexError: list index out of range
FAILED test/test_exploits.py::TestExploitScanner::test_exploit_checker[True-exploits_list2-product_info2-triage_info2-CRITICAL] - IndexError: list index out of range
FAILED test/test_exploits.py::TestExploitScanner::test_exploit_checker[False-exploits_list3-product_info3-triage_info3-CRITICAL] - IndexError: list index out of range
===== 12 failed, 1532 passed, 44 skipped, 40 warnings in 760.45s (0:12:40) =====

I haven't dug into these because I'm done work for the week (and need to switch to childcare) but that's an interesting set of failures. What I've learned from playing around with this today is that LegacyVersion was hiding some interesting conversions in our data, and I'm not sure the choices I made just to get it working were exactly the ones that we had before.

[terriko]

For the record: I think this PR will be replaced by something that uses cmp_version https://pypi.org/project/cmp_version/ but I need to update our licensing paperwork before that can happen.

[terriko]

Closing in favour of #3430