Format all the code using clang-format.

Add a script `format_code.sh` to easily format the code.

format_code.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/bash
+
+files=(
+"src/installer/kiwix-install.cpp"
+"src/searcher/kiwix-search.cpp"
+"src/reader/kiwix-read.cpp"
+"src/manager/kiwix-manage.cpp"
+"src/server/kiwix-serve.cpp"
+)
+
+for i in "${files[@]}"
+do
+  echo $i
+  clang-format -i -style=file $i
+done