Show when codes are about to expire

[michaelschattgen]

This PR adds a toggle under Settings -> Appearance to show when codes are about to expire. We will fade the color of the codes to a bright red when they're expiring in 7 seconds. Then when 3 seconds are left the codes will start to 'blink' as shown in the video below.

Fixes #411

20240918-1658-14.9308167.mp4

[alexbakker]

Functionally this looks good to me, but there are still some glitches here that I think will be hard to fix with the current approach. Scrolling through the list of entries seems to cause the state animations to get out of sync, you'll see the color switch from blue to red as new entries are loaded in and sometimes the expired state seems to get lost altogether.

I think it might be simpler to group the animations together in an AnimationSet and then seek to the right point in time inside the animation based on how many milliseconds are left until the code is refreshed. I've played around with this approach a little bit based on your branch: alexbakker@35ac51d. It seems to work well (though there might be some minor issues that I've missed). The downside is that setCurrentPlayTime is only available starting with API 26, but perhaps having this feature available for 95% of users is good enough.