Add LONG_TEST flag to cvedb test test_01_nist_scrape (and maybe others)

[terriko]

This test periodically fails, I think due to rate limiting because we get a 403 forbidden response:

E           aiohttp.client_exceptions.ClientResponseError: 403, message='Forbidden', url=URL('https://nvd.nist.gov/feeds/json/cve/1.1/nvdcve-1.1-2002.meta')

/opt/hostedtoolcache/Python/3.8.12/x64/lib/python3.8/site-packages/aiohttp/client_reqrep.py:1004: ClientResponseError

---------- coverage: platform linux, python 3.8.12-final-0 -----------
Coverage XML written to file coverage.xml

=========================== short test summary info ============================
FAILED test/test_cvedb.py::TestCVEDB::test_01_nist_scrape - aiohttp.client_ex...
============= 1 failed, 20 passed, 2 skipped in 173.85s (0:02:53) ==============

In the interests of being better users of NVD, I'm going to suggest that we move all of these tests to occur only in the LONG_TESTS phase so they don't run for every version of Python. We'll probably be able to run them again once we get the API key set up, but I think in the interest of better using a shared resource we might want to limit how often we run these tests anyhow.