Service: Move generated files jib diagonotic-tools.jar and .flattened-pom.xml and enhanced-openapi.json to the target directory

[ge0ffrey]

If I remove those two files and rerun the build, they appear automatically.

• They must not be checked in into Git.
• They should not live among the sources, but in be in the target directory

For both cases:

Proposal A) Put it under the target directory instead (recommended)

Proposal B) .gitignore it in all quickstarts, templates, models, etc

[ge0ffrey]

What about these files? Are those generated too?

Update: discussed with Radovan. The enhanced one should move too.

[mvanhorn]

Implemented in #2437 - relocates the flattened pom to target/, git-ignores and clean-removes the jib diagnostic-tools.jar (it must stay in src/main/jib because Quarkus container-image-jib only reads that fixed directory), and confirms the enhanced OpenAPI spec already writes under target/.