Revert "feat(percent): adds a percent class to numeric modules"

This reverts commit 82302e58f3b611f7ff6d686d1783b1c32914f7c9.

include/modules/battery.hpp

@@ -43,7 +43,6 @@ class Battery : public ALabel {
   int                   fd_;
   std::vector<int>      wds_;
   std::string           old_status_;
-  std::string           old_capacity_;
 };
 
 }  // namespace waybar::modules