Newly added OpenAI Platform by HTTP template could be improved.

1. manual and old User-Agent header in HttpRequest is not required.
2. description of LLD filter macros is the same for all of them.
3. one variable was declared without var
4. recursive function usage is not the best way. Better to avoid it.
5. it is better to avoid  .has_more method, or it should be handled better.
6. discovery uses #NAME macro for names. It better to use #ID to avoid creation of items with the same name.