Allow using OpenAI models for search in Khoj

- Init processor before search to instantiate `openai_api_key'
  from `khoj.yml'. The key is used to configure search with openai models

- To use OpenAI models for search in Khoj
  - Set `encoder' to name of an OpenAI model. E.g text-embedding-ada-002
  - Set `encoder-type' in `khoj.yml' to `src.utils.models.OpenAI'
  - Set `model-directory' to `null', as online model cannot be stored on disk

src/configure.py

@@ -34,14 +34,14 @@ def configure_server(args, required=False):
     else:
         state.config = args.config
 
+    # Initialize Processor from Config
+    state.processor_config = configure_processor(args.config.processor)
+
     # Initialize the search model from Config
     state.search_index_lock.acquire()
     state.model = configure_search(state.model, state.config, args.regenerate)
     state.search_index_lock.release()
 
-    # Initialize Processor from Config
-    state.processor_config = configure_processor(args.config.processor)
-
 
 @schedule.repeat(schedule.every(1).hour)
 def update_search_index():