Add a battery percent threshold

[Kvaibhav01]

Problem

We already have a low battery threshold feature. I'd like to have a similar feature under it where we could define how much the battery is charged.

Expected behavior

For example, if the battery reachers the set 80% charge, Alcove will notify via a message/icon/indication that "Battery charged" or something like that.

[chantalgo]

In the same note, I'd love Alcove to have the battery notifications (both full and low battery) for other bluetooth devices connected (mouse, keyboard) and maybe even other devices with the same user (other computers, phone, watch) just like airbuddy does