extensions_manager: Introduce typed callbacks for extensions_manager
This MR introduces typed callbacks as an alternative to the variadic argument pf_control
The rationale behind this MR is the same as in MR !3200 (merged).
The goal by introducing typed callbacks is to have a safer interface to plug into but also to move away from the mess around
va_list
(each compiler definesva_list
differently, needs to haveva_arg
everywhere, limited support in safer languages, prone to errors, ...).The driving factor behind this is to permit programming languages that don't have support for implementing a function that uses
va_list
to still be able to implement those callbacks.