[Feature] Option to Execute Command Upon Entering State

[WammKD]

As the title denotes, you could designate a command to run for when the state switches to a particular state; it would run once and that would be it until it switches to a different state (assuming the config. file has any command set for said new state).

I'm thinking this could be useful in, say, the battery module to execute a notification to dunst when entering state full or even run a command to suspend when entering the state critical.

I'm assuming it wouldn't involve much more as waybar has to keep track of the state, anyway, so it's just executing a user command along with changing the icon, etc. but I always could be mistaken.