[OpenAPI] allowlist apis and models

[newtork]

Please find similar setting names in the original OpenAPI generator.

Usage:

• In additionalProperties define modelsToGenerate and apisToGenerate. Use <space> or , as delimiter.

<plugin>
  <groupId>com.sap.cloud.sdk.datamodel</groupId>
  <artifactId>openapi-generator-maven-plugin</artifactId>
  <configuration>
    <additionalProperties>
      <apisToGenerate>Sodas,Orders</apisToGenerate>
      <modelsToGenerate>
        Order
        OrderWithTimestamp
        Soda
        SodaWithId
      </modelsToGenerate>
    </additionalProperties>

Note:

• To enable the generation of file SodasApi.java, the apisToGenerate field should contain Sodas (without suffix),
• If apisToGenerate is not defined, all APIs are allowed. Same with modelsToGenerate.

Definition of Done

• Functionality scope stated & covered
• Tests cover the scope above
• Error handling created / updated & covered by the tests above
• Documentation updated
• Release notes updated