BatteryIcon: Change color with charge percentage

[vkareh]

Silly little change to dynamically color the battery based on the charge left.

[github-actions[bot]]

Build size and comparison to main:

Section	Size	Difference
text	379028B	176B
data	948B	0B
bss	63488B	0B

[minacode]

Nice idea, I like it a lot! 😊 I think you could improve the contrast a little by using HSV colors and mapping the percentage to the hue interval between red and green. The brown in the second picture would become yellow. Lvgl can do the conversion to RGB.

[vkareh]

@minacode That's a brilliant suggestion! I've updated the code and added a new screenshot - looks way better, thanks!

[z3t0]

I love this change. Thank you.