ci: move wheels upload into its own job

[nikaro]

Since #3448 Windows wheels upload takes more than 1h. Let's try to do one upload (on Ubuntu) for all platforms.

[nikaro]

Copy/paste my comment from another PR of what could be an improvement:

Actually, GitHub runners come with AWS CLI installed so it should be even more straightforward to just use aws s3 sync ./wheelhouse s3://gensim-wheels (cf. https://docs.aws.amazon.com/cli/latest/reference/s3/sync.html).

In the meantime, i pushed this PR, and it works and has the advantage also to provide the wheels as GitHub artifacts (see at the bottom of the workflow summary page). Replacing wheelhouse-uploader by aws s3 sync should be very simple, but i don't have an AWS playground to test it.

[mpenkov]

OK, thanks for this. I'll merge and then see if anything further needs to be done.

[nikaro]

There is definitely something strange with Windows(?) wheels i guess: https://github.com/RaRe-Technologies/gensim/actions/runs/4384850019/jobs/7677703653