Fail or warn on build when application.properties/application.yaml is missing but application-<profile>.properties/application-<profile>.yaml is present

[yrodiere]

Description

When using profile aware files, we require the main file also to be present: https://quarkus.io/guides/config-reference#profile-aware-files

There's an actual reason for that, see here for an explanation: #37574 (comment)

However:

1. This requirement is easy to miss, and missing from some relevant places, e.g. YAML config documentation: https://quarkus.io/guides/config-yaml#profiles
2. The behavior when someone missed that requirement can be very confusing... the profile-aware file is simply ignored.

We should probably add a build-time check (at least) that detects profile-aware files, and fails the build (or warns... but I'd personally prefer a failure) if the corresponding application.properties/application.yaml file is missing, causing the profile-aware file to be ignored.

See #44807.

Implementation ideas

No response