Discuss: Unify translate operations over ai

I think that if this service should exist it has to exist in the ai_translate module, because if we start adding combinations of operation types based on what they solve rather on how they solve it and want to be consistent, there will probably be 100s of combinations in the AI core module, which will be impossible to manage.

Having a dedicated third party module or third party service for that makes more sense in that case.

Adding related issue; depending on where this issue lands, we could leverage ai_translate more.

@valthebald - code review is done from my side, the ai_translate.settings check and the setChatSystemRole method is important. Rest is optional if you think they are improvements, otherwise just skip.

I'll let Frederick do the feature review since he knows the module better, but from what I see in the code, it mostly works the same.

Oh also the PHPCS issues needs to be fixed.

Fixed most of the comments (2 left are for the future).
Also, brought back editing of default translation prompt (patch to have per-language left it hidden) and display of default prompt that has a condition

Thanks @valthebald for this MR!

I pushed and revert a commit in favour of this comments:

1. In ai_translate.install, is ai_translate_requirements() still required? I guess not.
2. In ai_translate.module, _ai_translate_check_default_provider_and_model() seems also outdated to me.
3. In AiTranslateForm.php, line 114, $default_model = $this->providerManager->getSimpleDefaultProviderOptions('chat'); should not use the chat provider type anymore.

I added some feedback as well after testing this in ✨ Fallback to ai_translate configuration Active
There are also some comments from Marcus to be addressed still

In general though it seems like the right direction, and is really helpful to have, thank you for the efforts here!