[TASK] Context menu rename "Export to .t3d" to "Export"

Patch renames the context menu options "Export to .t3d"
to "Export" and "Import from .t3d" to "Import".
The technical format detail is no good additional information
and also misleading since xml exports are possible, too.

Change-Id: I0d5bb6b1c390a6c74f58d41b06aac935bad82ec0
Resolves: #83552
Releases: master
Reviewed-on: https://review.typo3.org/55346


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>