Fix 404 link to Keycloak docs: securing_apps

[yada]

Broken link (404)

• URL: https://www.keycloak.org/docs/latest/securing_apps/index.html
• HTTP status: 404
• Found on: https://microcks.io/documentation/references/configuration/security-config/

What to do

• Replace with the current Keycloak documentation URL for securing applications.
• Prefer the latest stable docs URL (Keycloak doc URLs often change between versions).

Help needed

If you can’t find the correct Keycloak replacement URL, ask in comments and we’ll help identify it.