[RAG] Chunk management strategies and prompt optimization

...atafari/transformation/llm/services/OpenAiLlmService.java

datafari-tomcat/conf-datafari/rag.properties

...app/src/main/java/com/francelabs/datafari/api/RagAPI.java

...pp/src/main/java/com/francelabs/datafari/rag/Message.java

...in/java/com/francelabs/datafari/rag/OpenAiLlmService.java

...in/java/com/francelabs/datafari/rag/RagConfiguration.java

.../java/com/francelabs/datafari/rest/v2_0/ai/AiPowered.java

...n/java/com/francelabs/datafari/utils/rag/PromptUtils.java

...n/java/com/francelabs/datafari/utils/rag/VectorUtils.java

...c/main/resources/prompts/rag/template-fromTextSegment.txt

...p/src/main/resources/prompts/rag/template-mergeAllRag.txt

.../resources/prompts/rag/template-mergeAllRagByDocument.txt

...ri-webapp/src/main/resources/prompts/rag/template-rag.txt

...src/main/resources/prompts/rag/template-ragByDocument.txt

...rc/main/resources/prompts/rag/template-refine-initial.txt

...c/main/resources/prompts/rag/template-refine-refining.txt

.../summarization/template-initialPromptForSummarization.txt

...prompts/summarization/template-summarization-mergeAll.txt

...p/src/main/resources/prompts/template-fromTextSegment.txt

...ebapp/src/main/resources/prompts/template-mergeAllRag.txt