[FEAT] Chunked uploads

This allows chunked uploads by setting the parameter 'chunk_size'
to a value between 0 and the file size (both exclusive). It will
also only work if the version is 1.20 or newer.

The upload.py script supports this mode via the '-chunked'
parameter.

This also adds the capability to run the API request without
throttle so that it don't has to wait after each request.

See: https://www.mediawiki.org/wiki/API:Upload#Chunked_uploading

Change-Id: I80b2bba9e63832173d5b697db1f4ea419ca1122f
Merge "[FEAT] Chunked uploads"