Feature/configure flows (#345)

- Keeps processing in different flows separate so that data can go to different stores / collections etc.
- Potentially supports different processing flows
- Tidies the processing API with common base-classes for e.g. LLMs, and automatic configuration of 'clients' to use the right queue names in a flow

tests/test-embeddings

@@ -3,7 +3,12 @@
 import pulsar
 from trustgraph.clients.embeddings_client import EmbeddingsClient
 
-embed = EmbeddingsClient(pulsar_host="pulsar://localhost:6650")
+embed = EmbeddingsClient(
+    pulsar_host="pulsar://pulsar:6650",
+    input_queue="non-persistent://tg/request/embeddings:default",
+    output_queue="non-persistent://tg/response/embeddings:default",
+    subscriber="test1",
+)
 
 prompt="Write a funny limerick about a llama"
 
@@ -11,5 +16,3 @@ resp = embed.request(prompt)
 
 print(resp)
 
-
-