Fix naming of PC-88 and Spectravideo Icons

[WizzardSK]

Rename PC-88 icons to "PC-8001 - PC-8801" because the database and thumbnails has this name in libretro database, so the icons for pc88 will display corrrectly

Also renaming Spectravideo - SV to "Spectravideo - SVI-318 - SVI-328" according to libretro database.

Also added Arduboy and Commodore PET icons from https://github.com/Jaffacakelover/retroarch-assets/tree/monoc-ozo, thank you very much!

[WizzardSK]

Thanks for reviewing and approving.

[baxysquare]

Thanks @WizzardSK for this PR. You nailed it on the head, so I went ahead and merged it.

Our primary objective is to match the Libretro RDB listings and achieve an ongoing 1:1 ratio. As you've seen, some of these icons are designed and named in anticipation of RDBs that did not exist. We start with a No-Intro name if there is one, and if there's not, the first contributor does their best to name it. File naming is a hidden difficulty in the art of theme management! :-)

We absolutely prioritize renaming icons to match the RDB whenever it's added or has its file name updated, so if you see any others, please feel free to submit a PR. Also, if there are icons missing from the listings, don't hesitate to request them over on #433.