Fix environment variable naming inconsistencies in documentation (#5983)

[EricWittmann]

Summary

• Fixed environment variable naming to use underscores instead of hyphens throughout the security configuration documentation
• Corrected 21 environment variables across ~35 occurrences in assembly-configuring-registry-security.adoc
• Validated all corrections against source code (ConfigProperty annotations) and working examples (docker-compose files, integration tests)

Related Issue

Fixes #5983

Key Changes

The documentation incorrectly used hyphens in environment variable names. According to Quarkus/MicroProfile Config conventions, all hyphens and dots in property names must be converted to underscores when used as environment variables.

Examples of corrections:

• APICURIO_UI_AUTH_OIDC_CLIENT-ID → APICURIO_UI_AUTH_OIDC_CLIENT_ID
• QUARKUS_OIDC_TENANT-ENABLED → QUARKUS_OIDC_TENANT_ENABLED
• APICURIO_AUTH_ROLE-BASED-AUTHORIZATION → APICURIO_AUTH_ROLE_BASED_AUTHORIZATION
• APICURIO_AUTHN_BASIC-CLIENT-CREDENTIALS.ENABLED → APICURIO_AUTHN_BASIC_CLIENT_CREDENTIALS_ENABLED
• And 17 additional environment variables

Validation Performed

• ✅ Verified against source code configuration properties in UserInterfaceConfigProperties.java and other config classes
• ✅ Cross-referenced with all docker-compose examples in distro/docker-compose/
• ✅ Validated against integration test YAML files
• ✅ Confirmed no other documentation files contain these issues

Test Plan

• Review the diff to verify all environment variable names now use underscores consistently
• Spot-check a few corrected variables against the source code and examples to confirm correctness
• Verify the documentation renders correctly in AsciiDoc format