[C2] Integrate AI helper as feature

[ywarnier]

The AI Helper plugin in Chamilo 1.11.x has proven useful but relatively limited in regard to how AI models have been progressing over the last 48 months. Chamilo 2.0 shoud rise to the challenge and make AI integration an easily available set of features that is at the core of Chamilo (if so desired by the Chamilo admin).

Settings for the AI features will go into a new section "AI helpers" in the configuration settings page as follows:

• Enable AI helpers features: yes/no
• AI providers: JSON array with an example of how to configure one (a URL, an API key, a model to use, a temperature, an ID of organization and a monthly token limit by teacher)
• As learning path generator: enable/disable
• As exercise generator: enable/disable
• As open answers grader: enable/disable
• As tutor chatbot in courses: enable/disable
• As task grader: enable/disable
• As content analyser: enable/disable
• As image generator: enable/disable

These last 5 features are not implemented yet but will be at some point, possibly before the release of 2.0.

We already know how to support OpenAI gpt-3.5-turbo and DeepSeek chat, so we can use those 2 as example of how to configure them.

As for the features in Chamilo:

• split the AI generation of questions to a new page (new robot icon in the action bar) to make it more obvious. Show the Aiken format example on the Aiken page and the AI helper page, so that the format we expect is clear.
• keep a separate icon (robot icon in the action bar) for the generation of learning paths

On the course configuration page, add an "AI helpers" section with the same options to enable features as in the global settings. However, the section only appears if the global plugin is enabled, and each setting only appears if the corresponding global setting is enabled. If the settings were never changed before and they appear (=they have been enabled at the global level) then they are set to "yes" by default:

• As learning path generator: enable/disable
• As exercise generator: enable/disable
• As open answers grader: enable/disable
• As tutor chatbot in courses: enable/disable
• As task grader: enable/disable
• As content analyser: enable/disable
• As image generator: enable/disable

Later on, we will add more features, but these would already be a good achievement for 2.0.