Add ingestion pipeline with doc store strategies (#418)

.changeset/mighty-chicken-trade.md

examples/pipeline/ingestion.ts

packages/core/src/embeddings/types.ts

packages/core/src/extractors/types.ts

packages/core/src/index.ts

packages/core/src/ingestion/IngestionPipeline.ts

packages/core/src/ingestion/index.ts

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

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

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

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

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

packages/core/src/ingestion/types.ts

packages/core/src/nodeParsers/SentenceWindowNodeParser.ts

packages/core/src/nodeParsers/SimpleNodeParser.ts

packages/core/src/nodeParsers/types.ts

packages/core/src/storage/docStore/KVDocumentStore.ts

packages/core/src/storage/docStore/types.ts