Refactor A3 analysis structure by removing 'previous_context' from payload and prompts. Update documentation to reflect changes in context handling for improved clarity in data analysis.

Add Merithalle API integration with new service and tools for fetching site indicators. Update settings to include Merithalle API keys and base URL. Enhance A2 payload with site identifier and update prompts to utilize new indicators tool. Introduce example request JSON for A3 analysis.