Use adafruit_ticks

[jepler]

This cures problems where long-running animations would start to stutter on boards without monotonic_ns support (requires 7.x), while retaining full compatibility for 6.x.

I still need to test this on HW, which is why it's entered as a draft. Tested all animations on Feather S2 & NeoKey 5x6 Ortho Snap-Apart

As for RAM/CIRCUITPY usage,

• the adafruit_ticks mpy is 556 bytes (7.x)
• the net decrease in mpy size of led animation library is a mere 21 bytes across all files
• comparing the best (highest gc.mem_free()) of 5 runs before and after, 752 bytes more RAM are used after importing all animations

so, some additional RAM and disk space will be required by this change. I don't think we freeze animations in anywhere so this doesn't affect flash firmware size.

[jepler]

Working & tested the led_animation_all_animations.py example on the 5x6 ortho keypad with esp32s2.

[kattni]

Thanks to @jepler for putting this PR together. It's an excellent use of the new adafruit_ticks library.

However, after serious consideration, we've decided that the flash and RAM increases that come with this PR are not worth it. This library is already pushing the limits of many boards, and is beyond the limits of a few, so adding to that doesn't feel ideal. The example included that resets your board daily to keep timing accurate should be sufficient for most folks and, in the case of most projects, go unnoticed in action. If in the future we are only supporting boards that have significant flash and RAM, we can reconsider. Until that time, we'll deal with the timing issues to maintain size constraints.