Ordering built-in and custom data providers (#414)

So custom data providers could be executed after built-in data providers. This will allow not only create additional resources, but also update resources (already) generated by Allure standard data providers.

I didn't want to add explicit ordering in data providers. Data provider dependency management is also an overkill IMO. So, there are minimal changes to add ordering required.

Thoughts?
I don't like magic constants. IMO better use enum. We can use enum with ordinal value.