Utils: Add PathString to improve memory usage for longer paths

Change-Id: I90bca7eddfc4823406f1320a7f6e7836d53c3425
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/smallstring.h

@@ -866,6 +866,7 @@ std::vector<Type> clone(const std::vector<Type> &vector)
 }
 
 using SmallString = BasicSmallString<31>;
+using PathString = BasicSmallString<191>;
 
 } // namespace Utils
 

src/libs/utils/smallstringvector.h

@@ -158,7 +158,7 @@ private:
 };
 
 using SmallStringVector = BasicSmallStringVector<31>;
-
+using PathStringVector = BasicSmallStringVector<191>;
 } // namespace Utils;
 
 #pragma pop_macro("noexcept")