[security-getting-started.adoc] Review the `Secure a Quarkus application with Basic authentication` chapter

:This task is done when:

• *[If there is/will be enough ref information to warrant a dedicated ref topic at this time without going over scope... ] *A new diataxis template Reference adoc is created and completed containing the Quarkus Security API endpoints reference information:
  

• Existing content in security-getting-started.adoc (now in 3 new diataxis topics see below) and proposed on the Miro board as being a requirement in the new diataxis framework, is migrated into a Reference topic.
• Minimal style effort.
• Xrefs and links are updated accordingly throughout the other topics in the repo.
• All is SME approved and merged to main.

Original state before poc: https://github.com/quarkusio/quarkus/pull/27009/files?short_path=3b6266f#diff-3b6266f9cc9ea2d5e564f8c57520e0a3f44c5372b5e1b35f624463f5517a8ada
Note: Some of the recomposing work is done, meaning that all of the original security-getting-started.adoc is composed into these 3 topics:

1. https://github.com/quarkusio/quarkus/blob/main/docs/src/main/asciidoc/security-basic-authentication-tutorial.adoc
2. https://github.com/quarkusio/quarkus/blob/main/docs/src/main/asciidoc/security-basic-authentication-howto.adoc
3. https://github.com/quarkusio/quarkus/blob/main/docs/src/main/asciidoc/security-basic-authentication-concept.adoc