Issue 77 incorporate playable games into individual game pages

[TobbleCobble]

Change Summary

The cover image on the game page is now replaced by an iframe linked to itch. Database now stores values for game embed id, game width and game height. If there is no value for game embed id, the game page will still show the cover image

Change Form

• The pull request title has an issue number
• The change works by "Smoke testing" or quick testing
• The change has tests
• The change has documentation

Other Information

Game scaling may not be an exact match to itch, but this shouldn't be a problem for most games

Related issue

• Resolve Incorporate playable games into individual game pages #77