feat: Add doc store strategies to VectorStoreIndex.fromDocuments (#646)

.changeset/young-bananas-wave.md

packages/core/src/indices/vectorStore/index.ts

packages/core/src/ingestion/IngestionPipeline.ts

...core/src/ingestion/strategies/UpsertsAndDeleteStrategy.ts

packages/core/src/ingestion/strategies/index.ts

packages/core/tests/indices/VectorStoreIndex.test.ts