[TASK] EM: move "upload t3x" to tab Remote Repository

In an attempt to have the Remote Repository tab become a place to
search and install new extensions, the tiny upload .t3x icon next
to the filter textbox in "Local Extension List" should be moved.

Change-Id: I198dc95ecd8dcd953f699428d7118a9670d6b277
Resolves: #29587
Releases: 4.6
Reviewed-on: http://review.typo3.org/4893
Tested-by: Soren Malling
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Steffen Gebert
Tested-by: Steffen Gebert