This starts the rewrite of the dynamic badges. I've pulled into BaseService an initial version of the query param validation from #2325.
I've extended from BaseJsonService to avoid duplicating the deserialization logic, though it means there is a bit of duplicated code among the three dynamic services. The way to unravel this would be to move the logic from `_requestJson` and friends from the base classes into functions so DynamicJson can inherit from BaseDynamic. Would that be worth it?
This introduces a regression of #1446 for this badge.
Close#2345