[General] Images offline cache

[arielj]

This PR adds a mechanism to cache game images in the file system to be overcome the issue with the chrome's cache having a limit in size.

How it works:

• added a custom protocol imagecache:// intercepted by electron to respond with a local file
• added a CachedImage component that first tries to use the cache, and, if the request fails, it fallback to the original url
• added an images_cache module with a function that will convert a imagecache:// url into a local file response and, if the file is not already cached, cache it in the background

this was suprisingly way easier than I expected xD

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Use the following Checklist if you have changed something on the Backend or Frontend:

• Tested the feature and it's working on a current and clean install.
• Tested the main App features and they are still working on a current and clean install. (Login, Install, Play, Uninstall, Move games, etc.)
• Created / Updated Tests (If necessary)
• Created / Updated documentation (If necessary)

[Nocccer]

LGTM. I would love to get rid of placing files directly into electron folder.

[flavioislima]

Testing here and it works fine for the library but not for the game page.
Also, would not be better to use the appNames for the images instead of a hash? Not sure if that is important, just a thought.

[arielj]

Testing here and it works fine for the library but not for the game page. Also, would not be better to use the appNames for the images instead of a hash? Not sure if that is important, just a thought.

I'll check the game image!

I thought about using the app name, but then we have 2 different sizes for the main image plus the logo, so I would have to come up with a pattern to generate file names and also I would have to pass the app name and image type around in the url (I guess I could get the requested size from the url), but it sounds like too complicated for something that is just a cache, the digest ensures it's unique and it's really simple

[arielj]

@flavioislima I fixed the issue with the game image (added a fallback src to use the smaller one if it fails)

I couldn't use heroic/Cache/images, electron clears that folder at boot

[flavioislima]

NIce, Looks good now! Ready to merge! 👍🏽