Consider enabling decentralized per-module security configuration

When building a large application with many modules I want to be able to define spring security configuration in each module so that the application security configuration gets assembled out of the configuration in each module. I want to able to create re-usable modules drop them into different application and have their security configuration added to the app's security configuration.

Spring security configuration is centralized and module specific security configuration has to be defined outside in the global location where spring security is configured at the level of the app. This centralized configuration makes testing modules in isolation harder since the security configuration is located outside the module. Enhancing spring security to enable decentralized module specific security configuration, where the app can combine the security settings from all the modules is very helpful.

Related gh-13266

No files, tests, or entry points are named; begin by reviewing the related issue gh-13266 and locating Spring Security's existing application-level configuration model. The work is complete when reusable modules can contribute security configuration that the application assembles while still allowing modules to be tested in isolation.