[bug][finch] Infrastructure classes are output to /scala folder

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

Types are written to the scala folder rather than a standard package folder structure (as defined by packageName).

For example, defining:

• packageName=org.openapitools.finchy
• apiPackage=org.openapitools.finchy.apis
• modelPackage=org.openapitools.finchy.models

openapi-generator version

4.0.0, possibly affects earlier versions

OpenAPI declaration file content or url

https://github.com/OAI/OpenAPI-Specification/blob/master/examples/v2.0/json/api-with-examples.json

Command line used for generation

OPENAPI_GENERATOR_VERSION=4.0.0 openapi-generator generate \
  -g scala-finch \
  -i https://raw.githubusercontent.com/OAI/OpenAPI-Specification/master/examples/v2.0/json/api-with-examples.json \
  -o finchy \
  --additional-properties=packageName=org.openapitools.finchy,apiPackage=org.openapitools.finchy.apis,modelPackage=org.openapitools.finchy.models

where openapi-generator is our launcher script (https://github.com/OpenAPITools/openapi-generator/blob/master/bin/utils/openapi-generator-cli.sh)

Steps to reproduce

Generate using command above, inspect output:

[main] WARN  o.o.c.ignore.CodegenIgnoreProcessor - Output directory does not exist, or is inaccessible. No file (.openapi-generator-ignore) will be evaluated.
[main] INFO  o.o.codegen.DefaultGenerator - OpenAPI Generator: scala-finch (server)
[main] INFO  o.o.codegen.DefaultGenerator - Generator 'scala-finch' is considered stable.
[main] WARN  o.o.codegen.utils.URLPathUtils - 'host' (OAS 2.0) or 'servers' (OAS 3.0) not defined in the spec. Default to [http://localhost] for server URL [http://localhost/]
[main] WARN  o.o.codegen.utils.URLPathUtils - 'host' (OAS 2.0) or 'servers' (OAS 3.0) not defined in the spec. Default to [http://localhost] for server URL [http://localhost/]
[main] WARN  o.o.codegen.utils.URLPathUtils - 'host' (OAS 2.0) or 'servers' (OAS 3.0) not defined in the spec. Default to [http://localhost] for server URL [http://localhost/]
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/src/main/scala/org/openapitools/finchy/apis/DefaultApi.scala
[main] WARN  o.o.codegen.utils.URLPathUtils - 'host' (OAS 2.0) or 'servers' (OAS 3.0) not defined in the spec. Default to [http://localhost] for server URL [http://localhost/]
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/README.md
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/build.sbt
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/src/main/scala/Server.scala
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/src/main/scala/DataAccessor.scala
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/project/build.properties
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/project/plugins.sbt
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/sbt
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/src/main/scala/endpoint.scala
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/src/main/scala/errors.scala
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/.openapi-generator-ignore
[main] INFO  o.o.codegen.AbstractGenerator - writing file /Users/jim/projects/openapi-generator/.bak/finchy/.openapi-generator/VERSION

Suggest a fix

Set the target folder for infrastructural types to the package output path.

Run the documented scala-finch command with the linked OpenAPI example and inspect the generated src/main/scala paths. Compare the packaged API and model outputs with infrastructure files such as Server.scala, DataAccessor.scala, endpoint.scala, and errors.scala. Done means infrastructure types are emitted under the configured package output path rather than directly in the scala folder.