Configure kleopatra with different application name for GPD and VSD

* src/gpg4win.mk.in (KLEOPATRA_APPLICATION_NAME): New.
* src/Makefile.am (gpg4win_pkg_kleopatra_configure): Add
-DKLEOPATRA_APPLICATION_NAME option.

Using different application names for kleopatra for GPD and VSD makes
it possible to run kleopatra built for GPD concurrently with kleopatra
built for VSD (and concurrently with kleopatra built for Gpg4win).

(cherry picked from commit 76026ecfd79e4b55ec567c38ea5c450265d40ffe)
(without changes related to KLEOPATRA_ICON_DIR)

• GnuPG-bug-id: T7528