Check file size less than UPLOAD_MAX_SIZE

[GraemeWatt]

I've increased the DEFAULT_TIMEOUT for the hepdata-cli package to allow for the increased request timeout in the Kubernetes settings from 1 minute to 5 minutes. I've also added a check to the hepdata-cli code that the uploaded file size does not exceed UPLOAD_MAX_SIZE. However, this limit could easily be modified in client-side code, so the check should also be made in the server-side code. Currently, we only make the UPLOAD_MAX_SIZE check for web uploads and not for CLI uploads. This PR modifies process_payload to make the check for both. Alternatively, the Flask MAX_CONTENT_LENGTH could be set, but this did not return an informative error message when I tried it. I've written a new test test_upload_max_size in tests/records_test.py.

[coveralls]

Coverage increased (+0.02%) to 86.831% when pulling e9cfbf1 on check-uploadmaxsize into d03c1c0 on master.

[alisonrclarke]

Looks good to me.

[GraemeWatt]

The check for UPLOAD_MAX_SIZE only in process_payload will first save the file to disk, which is not ideal for a very large upload. I've added the MAX_CONTENT_LENGTH (= UPLOAD_MAX_SIZE) Flask configuration key to limit the size of the incoming request data. It gives an error message ConnectionError: ('Connection aborted.', BrokenPipeError(32, 'Broken pipe')) when testing locally with the hepdata-cli, but the Flask docs indicate that it should return the correct 413 Request Entity Too Large status response when running the app with a production WSGI server.