feature: maintain battery in a certain range

[tangb4c]

Allow battery tool to maintain battery between in a certain range.
Syntax: battery maintain min-max
Battery tool turn off charging above the maximum value, and on below the minimum value.
eg: battery maintain 20-70
eg: battery maintain 30-30

[Lonec-L]

Possibly closes #222

[Ben7on]

stop it when it's higher than lower_thres

According to this if condition, It seems it will stop only once it's higher than upper_threshold

if [[ "$battery_percentage" -ge "$upper_threshold" && "$is_charging" == "enabled" ]]; then

[FlyfishO25]

Yeah, forgive my misunderstanding, your code is correct :)

[tangb4c]

@actuallymentor do you have time to merge this MR?

[actuallymentor]

Thanks a lot for your work @tangb4c! And apologies for my late response. My response times vary a lot depending on how busy work is :)

The only request I have is to add a few extra comments explaining what your code does. I like to leave many comments so that new contributors can easily figure out what things do.

Please tag me when you added them and I will gratefully merge!

[FeeJai]

+1. May I request a GUI feature for this too?

[seefood]

@tangb4c are you adding the remarks or would you like some 3rd party help with an update PR? :)

[tangb4c]

@tangb4c are you adding the remarks or would you like some 3rd party help with an update PR? :)

@seefood Do me a favor, pls, :D

[actuallymentor]

Closing so we can keep this central in #261, if that was in error let me know!