Added a to_lower_case function

sandbox/server/http/http_tools.cpp

@@ -1,5 +1,14 @@
 #include "http_tools.h"
 
+std::string string_to_lower(std::string& str)
+{
+    for (int i = 0; i < str.length(); i++)
+    {
+        str[i] = std::tolower(str[i]);
+    }
+    return str;
+}
+
 std::string string_to_upper(std::string& str)
 {
     for (int i = 0; i < str.length(); i++)

sandbox/server/http/http_tools.h

@@ -2,6 +2,7 @@
 
 #include <commun.h>
 
+std::string string_to_lower(std::string& str);
 std::string string_to_upper(std::string& str);
 std::unique_ptr<std::vector<std::string>> string_split(std::string s, std::string delimiter, int cpt = -1);
 std::string string_trim(const std::string& str, const std::string& whitespace = " ");