feat: import and export database as json (#2577)

[b31ngd3v]

part of #2577

This is, incidentally, a pro for the "make a bunch of json files that can be re-loaded" theory, since they could and would be chopped into more manageable year/month chunks.

Originally posted by @terriko in #2577 (comment)

Export Database as bunch of JSON files chopped up by years

Import Database from bunch of JSON files chopped up by years

Directory structure of exported data

[terriko]

I'll need to come back and code review this more carefully when I've got more time, but I wanted to say that this looks like the right direction and I'm very excited about it! 👍 👍 👍

[codecov-commenter]

Codecov Report

Merging #2774 (7e66e77) into main (fbe3cac) will decrease coverage by 0.81%.
The diff coverage is 15.87%.

@@            Coverage Diff             @@
##             main    #2774      +/-   ##
==========================================
- Coverage   82.62%   81.81%   -0.81%     
==========================================
  Files         646      646              
  Lines       10018    10139     +121     
  Branches     1334     1363      +29     
==========================================
+ Hits         8277     8295      +18     
- Misses       1403     1495      +92     
- Partials      338      349      +11     

Flag	Coverage Δ
longtests	80.74% <15.87%> (+3.72%)	⬆️
win-longtests	79.13% <15.87%> (-1.10%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
cve_bin_tool/cvedb.py	56.33% <15.25%> (-15.40%)	⬇️
cve_bin_tool/cli.py	67.08% <25.00%> (-0.76%)	⬇️
cve_bin_tool/data_sources/gad_source.py	70.00% <0.00%> (-16.25%)	⬇️
cve_bin_tool/data_sources/nvd_source.py	56.04% <0.00%> (-0.81%)	⬇️
cve_bin_tool/output_engine/console.py	97.60% <0.00%> (+1.59%)	⬆️
test/test_cli.py	86.23% <0.00%> (+2.17%)	⬆️
cve_bin_tool/data_sources/osv_source.py	81.77% <0.00%> (+2.33%)	⬆️
cve_bin_tool/data_sources/redhat_source.py	66.22% <0.00%> (+3.31%)	⬆️
cve_bin_tool/output_engine/pdfbuilder.py	91.07% <0.00%> (+7.14%)	⬆️

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[terriko]

Sorry it took me so long to get back to this! It's looking really good. I'm going to merge it then probably take it to some folk who were considering helping us with a mirror system -- they may have some more feedback once they try it out, but I think it'll be easier to do once it's merged. Thank you so much for working on this!