Add push_documents method to Compass client for asynchronous document processing

[javier-cohere]

We added a new endpoint to Compass that allows to send file bytes for their parsing and indexing using barckground jobs in the server:

/v2/indexes/{index_name}/documents

This PR is to add a function to the SDK that allows to send files to that endpoint. Function parse_and_insert_doc gets a filename and opens the document, gets its bytes, generates a file id if necessary, and sends the bytes to Compass.

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[benrules3]

Left one nit on documentation - can you DM me when resolved and I'll approve? Approval has to be on most recent push... Then we should be good to merge.