Ensure columns use JSON instead of Python dicts

This change will fully fix #66

The issue affects all columns that contain Python dictionaries stored via the str() method. So for sure the leadershipSkills column and purchaseUrls are affected.

This currently has data like:

{'brawl': False, 'commander': True, 'oathbreaker': False}

This is a valid string version of Python's native dict type but is not useful outside of ptyhon. Given that any language can interact with an SQLite file, but not all of them can decode Pythong dicts - this is sad. 😿 To fix this it will now json.dumps the dict into a valid JSON syntax object.

The after effect is:

{"brawl": false, "commander": true, "oathbreaker": false}

Happy JSON is happy 😸

The great thing about this PR is that it has the bonus effect of fixing the CSVs as well. As of RN, the CSVs also would look like:

,"{'cardKingdomFoil': 'https://mtgjson.com/links/4e3f626b14b25f54', 'tcgplayer': 'https://mtgjson.com/links/74fc1dd3bbb80489'}",

However after the fix they look like:

,"{""cardKingdomFoil"": ""https://mtgjson.com/links/4e3f626b14b25f54"", ""tcgplayer"": ""https://mtgjson.com/links/74fc1dd3bbb80489""}",

This is important since both Excel and Google Sheets will support JSON methods, but don't support python dicts.

Excel: https://support.microsoft.com/en-us/office/parse-text-as-json-or-xml-power-query-7436916b-210a-4299-83dd-8531a1d5e945
Sheets: Done via Apps Script

mtgjson / mtgsqlive

Ensure columns use JSON instead of Python dicts #83