Rename "Business Automation" category to "Automation"

As requested by @ricardozanini, see https://github.com/quarkusio/quarkus/issues/55974#issuecomment-5357781235

As discussed in https://github.com/quarkusio/quarkus/issues/55974, this is non trivial, because knowledge of categories is spread across five sources. :)

We should probably get most of done, before attempting this. Even once the sources of truth are streamlined, there are some challenges:

• Is "automation" the right category, or is too broad?
• How will category renaming work? We can modify extension yamls and the source-of-truth files, but the "business automation" category is likely to linger in our tooling for a while, unless we put in an explicit alias infrastructure. Quarkiverse extensions like Camunda use it, as well as the de-platformed Drools extensions.

The current places the text lives is:

• https://github.com/quarkusio/quarkus/blob/478e5fe6c974b9cefce07598e79db6359a1ab7d0/docs/src/main/java/io/quarkus/docs/generation/YamlMetadataGenerator.java#L385
• https://github.com/quarkusio/quarkus-platform/blob/6088b7ca2d9fb0a76bea1b23c6b9ace4386138eb/src/main/resources/extensions-overrides.json#L16
• https://github.com/quarkusio/quarkusio.github.io/blob/30ddc373737072a3c2a35f7b0ede3b7a636e63b8/_guides/doc-reference.adoc#L424
• https://github.com/quarkusio/quarkusio.github.io/blob/30ddc373737072a3c2a35f7b0ede3b7a636e63b8/_data/versioned/2-16/index/quarkus.yaml#L712 plus many other historic guide index pages and translated guides.