Add Final Fantasy Shop channel

[dylbyl]

Description

Adds a channel that mimics Final Fantasy 7's shops. Donations cause the menu to "scroll" down and reveal new Square Enix themed items with unique descriptions and icons. The item's price is the amount donated, and larger donations result in "better" items. A different "theme" is used each time the channel loads to make it evoke different games: FF7, FF8, Chrono Trigger, Dragon Quest, FF4. New themes and items can easily be added or removed.

Checklist:

• [x] I have read and followed the requirements in the Contributing document.
• [x] My code has been tested.
• [x] My commit title follows Conventional Commits formatting.
• [x] All the code is my own, or is code I have the rights to, and is being made available under the Apache License Version 2.0.
• [x] My channel contains no first-party Nintendo assets.
• [x] I understand that GamesDoneQuick may reject, make changes to, or choose not to show this channel on broadcast, and that discussion or merging does not guarantee the work will be used.

[dylbyl]

I've added a fake scrollbar to better visualize the scrolling action. This resets its position each time the channel loads, or if the bar reaches the bottom. Its background is also tied to the theme.

[dylbyl]

@chrishanel The scrollbar messed up the alignment of the cursor and the bottom item, so I snuck in another commit for that. It says above that I dismissed your review, so I'm sorry if you need to re-approve. I'll be more aware of that next time!

[chrishanel]

first of all how dare you

(edit: lol no worries, taking another look shortly)