Supporting System Icons In Modules

[oisanjaya]

I propose that all modules inherit from AIconLabel instead of ALabel to support proper icon from system instead (or in adition of) font glyps as icon.
As AIconLabel is also a decendant of ALabel, I think it doesn't introduce much changes to adapt current module's code to acomodate parent changes.
My idea is allowing some marking langugae inside "format" and/or "format-icons" configuration to refer some system's icon.
Maybe better using already used marking/protocol system like Rofi's parsing options. Then icons would be marked with "\0icon\x1f<icon-name>\n". User then may replace <icon-name> using one of xdg-icon-resource names. This way user can install additional icons to be used for their Waybar, and it will change according to user's current icon theme.
Potential problems: handling more than one icon in a module may be render code too complicated, so maybe its better to parse at most one icon reference from config file and ignore and remove remaining icon marking so it wouldn't become label.

[oisanjaya]

made PR #4719