Check secadv/ against secjson/, and fix the latter where necessary

[levitte]

It appears that some of the JSON entries lack data that's present in the advisory texts

A few examples, taken from openssl/openssl#27577:

• secjson/CVE-2023-0215.json is missing attributions present in secadv/20230207.txt
• secjson/CVE-2023-1255.json is missing attributions present in secadv/20230420.txt, and has an incorrect advisory text URL.
• secjson/CVE-2022-0778.json is missing attributions present in secadv/20220315.txt
• secjson/CVE-2021-3712.json is missing attributions present in secadv/20210824.txt

We need to go through all advisories, at least recent enough, to check that data matches, and fix the JSON data where there's a difference (we do assume that the advisory text files are correct records).

[t8m]

@levitte We do not seem to be parsing reporter just finder for reporting credits.