Improve performance of FileSystemGraphObjectStore getEntity

[austinkelleher]

The getEntity function in FileSystemGraphObjectStore is currently iterating every entity on disk to catch duplicate entity keys. We should trust the DuplicateKeyTracker and return the first entity with the given key. On integrations that ingest a large amount of data, we do not want to iterate every local file.

See: https://github.com/JupiterOne/sdk/blob/master/packages/integration-sdk-runtime/src/storage/FileSystemGraphObjectStore/FileSystemGraphObjectStore.ts#L67

[austinkelleher]

This is one small change, but a significant improvement would be to create an in-memory Map that tracks the file path of the file by _key and the index of the entity in the file. That would drastically improve the performance of local entity searches.

[austinkelleher]

Fixed in #454