Reuse embeddings

Closes #663

Author: edeandrea

rag/easy-rag/runtime/src/main/java/io/quarkiverse/langchain4j/easyrag/runtime/EasyRagRecorder.java

@@ -59,6 +59,12 @@ public void ingest(EasyRagConfig config, BeanContainer beanContainer) {
                 ingestDocumentsFromFilesystem(config, embeddingStore, embeddingModel);
                 LOGGER.infof("Writing embeddings to %s", embeddingsFile);
                 ((InMemoryEmbeddingStore<TextSegment>) embeddingStore).serializeToFile(embeddingsFile);
+            } else {
+                // This is here because in the case where the file exists, the EmbeddingStore will be
+                // lazily initialized upon first use. We want it eagerly initialized.
+                // We need to call a method on the bean instance to eagerly initialize it
+                // https://github.com/quarkusio/quarkus/issues/41159 may make this less "hacky" in the future
+                embeddingStore.toString();
             }
         } else {
             ingestDocumentsFromFilesystem(config, embeddingStore, embeddingModel);