ConfigProvider.getConfig() should take profile into account

[loicmathieu]

Describe the bug
Following the discussion for #4869 it appears that when accessing the Config object from ConfigProvider.getConfig(), profiles is not taken into account.

Reading the spec, this is the prefered way to access the configuration programmaticaly

The current configuration of an application can be accessed via ConfigProvider#getConfig().

https://github.com/eclipse/microprofile-config#design

Expected behavior
ConfigProvider.getConfig() take profiles into account.

Additional context
It has been suggested to use a ConfigResolver, but this is less obvious for a user and some internal Quarkus code already use ConfigProvider.getConfig() so it is a bug already present in Quarkus.

[dmlloyd]

The bug is that ConfigProvider.getConfig() and ConfigProviderResolver.instance().getConfig() are unfortunately returning different instances. This is codified in the existing bug report #4653 #4512 (sorry, had written the wrong issue number).

It does not have any relationship to profiles.

[loicmathieu]

@dmlloyd this is not #4653 as it's about GraalVM updates.

I was a mis-understanding relationship to profiles, but anyway, the important thing is to fix it to be able to offers an undertandable (and standard) way to access the config programmatically.

[dmlloyd]

I guess I had a clipboard/brain malfunction. I corrected the issue link.

[loicmathieu]

OK , closed this one and link the documentation PR to #4512