Modules: Make ast_module_info->self available to auxiliary sources.

ast_module_info->self is often needed to register items with the core.  Many
modules have ad-hoc code to make this pointer available to auxiliary sources.
This change updates the module build process to make the needed information
available to all sources in a module.

ASTERISK-25056 #close
Reported by: Corey Farrell

Change-Id: I18c8cd58fbcb1b708425f6757becaeca9fa91815