feat(disk)!: handle multiple disks at once

include/modules/disk.hpp

@@ -4,6 +4,7 @@
 #include <sys/statvfs.h>
 
 #include <fstream>
+#include <vector>
 
 #include "ALabel.hpp"
 #include "util/format.hpp"
@@ -19,7 +20,9 @@ class Disk : public ALabel {
 
  private:
   util::SleeperThread thread_;
-  std::string path_;
+  std::string header_;
+  std::vector<std::string> paths_;
+  std::string separator_;
   std::string unit_;
 
   float calc_specific_divisor(const std::string divisor);