Allow to define a provider of values for a macro parameter

The idea is that defining an Enum type for a macro parameter is often not enough: we might need to be able to get dynamically the returned values to display for a wiki macro parameter. And we might also to allow custom values on top of predefined values.
Right now the only way to deal with those scenario is to define a custom displayer which is tedious. It would be easier to be able to define a component role and to be able to specify the hint of the component implementation for getting the values.

Example of needs for such usecases are the JIRA charts macro where we want to allow set of predefined and custom jira fields, and async macro context elements.