[TASK] EM: Move Upload button to top button menu

Moves the button Upload Extension directly to
the top main button menu.

Change-Id: I1905d8fa9a31a5cfd3b538e3f60f7c8507833bd8
Fixes: #33868
Releases: 4.7
Reviewed-on: http://review.typo3.org/8989
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Stefan Galinski
Tested-by: Stefan Galinski
Reviewed-by: Steffen Gebert
Tested-by: Steffen Gebert