Replace ConfigFileApplicationListener and rework application properties support #22497
Description
There are quite a few issues arising from our current application.properties processing code that we'd like to fix. Specifically we'd like to address the following concerns:
- Create distinct classes for different areas of functionality:
- Calling EnvironmentPostProcessors
- Adding the RandomPropertySource
- Moving the defaultPropertySource to the end
- Loading application.properties and application.yml files
- Process config data files in phases, and stop profile specific files/documents from activating further profiles
- Support custom imports so that we can support volume mounts
- Provided a pluggable API that could make it possible for Spring Cloud to drop the need for
bootstrapproperties - Support activation conditions for documents such as
on-cloudandon-profile