util: Move TrimString(...). Introduce default pattern (trims whitespace). Add NODISCARD.

src/util/string.h

@@ -11,6 +11,16 @@
 #include <string>
 #include <vector>
 
+NODISCARD inline std::string TrimString(const std::string& str, const std::string& pattern = " \f\n\r\t\v")
+{
+    std::string::size_type front = str.find_first_not_of(pattern);
+    if (front == std::string::npos) {
+        return std::string();
+    }
+    std::string::size_type end = str.find_last_not_of(pattern);
+    return str.substr(front, end - front + 1);
+}
+
 /**
  * Join a list of items
  *