[BUG] posters and thumbnails

[ReenigneArcher]

Describe the bug When a poster on igdb is changed, the new poster is added to plex, but not as the primary.

When any image is removed from igdb, it is not removed from plex.

To Reproduce Steps to reproduce the behavior:

1. [e.g. Go to '...']
2. [e.g. Click on '....']
3. [e.g. Scroll down to '....']
4. [e.g. See error]

Expected behavior Replace the old igdb poster with the new poster (use igdb-poster as the name)

Remove photos removed from igdb (need to add igdb as a prefix in the name, and check if they're all still on the site)

Screenshots If applicable, add screenshots to help explain your problem.

Server (please complete the following information):

• OS: [e.g. Windows, Ubuntu]
• Architecture [e.g. 32 bit, 64 bit, arm]
• Version [e.g. 20210130]

Client(please complete the following information if applicable):

• Device: [e.g. Nvidia Shield TV, Bravia TV, Fire Stick 4k, Pixel 3a]
• OS: [e.g. Android 11]
• App: [e.g. Moonlight]
• App Version: [e.g. 9.8.1 (Apps Drawer... Apps/Games/Information]
• Connection: [e.g. Wireless 2.4 GHz, Wireless 5 GHz, Ethernet 1GB/s]

Gamepad(please complete the following information if applicable):

• Manufacturer: [e.g. Microsoft, Sony, Logitech]
• Type: [e.g. Xbox One, Xbox One S/X, Xbox Series X/S, PS3, PS4]
• Connection: [e.g. USB, Bluetooth, Dongle, WiFi]

Additional context Add any other context about the problem here.

[ReenigneArcher]

Changed method for posters. As there's only 1 for igdb I've renamed the image name to igdb-game_name... Then I'll always replace it. Plex will use the image form cache if it exists, otherwise it will fetch the image from the url.

For the art, I cannot delete the items using the standard agent functions. So closing this for now, but might re-visit deleting removed images using plexapi.