spring-boot: move oauth2 configuration to secret-samples

[mshima]

OIDC configuration should be customized by each application depending on its environment. To encourage this, the configuration should be moved to secret-samples, forcing users to explicitly customize it for the prod profile.

The dev profile enables secret-samples by default, and we also enable it in the scripts. Otherwise, the default configuration would be applied.

The suggested fix in #30206 is to remove the offline_access scope.
The offline_access scope was added a few years ago and, as far as I know, it is mainly used by the Ionic blueprint.

The initially proposed fix resulted in several PRs:

• Closes fix: remove offline_access from default OAuth2 scope #30254
• Closes fix: conditional offline_access scope for Keycloak 26+ SSO #30206 #32431
• Closes Remove offline_access from default OAuth2 scope #32173
• Closes fix: remove offline_access from default OAuth2 scope to fix SSO #32358
• Closes fix: remove offline_access from default OAuth2 scope #32515

However, these PRs mainly introduce alternative configurations that are expected to be customized in production environments anyway.

Fixes #30206.

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