feat: support partial translation via apply_to array

[n-o-u-r-h-a-n]

Context

AI/ai-sdk-java-backlog#341.

Apply_to array is now supported instead of being set to null to support partial translation of the user's prompt.

Feature scope:

• TranslationApplyToSelector a new class was created as a convenience builder for SAPDocumentTranslationApplyToSelector.
• Sample code was updated.
• Translation test was updated in OrchestrationTest.
  • New tests were added in OrchestrationModuleConfigTest to cover the new class methods.

Definition of Done

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

[CharlesDuboisSAP]

Make sure the API that you write is fluent.

Not readable doesn't flow:

.withApplyTo(
  List.of(
    TranslationApplyToSelector.placeholders(List.of("exam_type", "topic")),
    TranslationApplyToSelector.templateRoles(TemplateRole.ASSISTANT)))

Readable and flows:

.applyToPlaceholders("exam_type", "topic")
.applyToTemplateRoles(TemplateRole.ASSISTANT)

[CharlesDuboisSAP]

Mistake from your old PR:
sourceLanguage isn't being used and applied.
You should fix it and improve the unit test to make sure it is being used and applied.

[n-o-u-r-h-a-n]

It's used in OrchestrationService class and all other test classes.What do you mean exactly?