print/rtf2latex2e: Update to 2.2.3

Strip binary in post-install target.
Add LICENSE_FILE.
Add TEST_TARGET and TESTING_UNSAFE.

Changelog:
https://sourceforge.net/projects/rtf2latex2e/files/rtf2latex2e-unix/

PR: 282106
Approved by: martin.dieringer@gmx.de (maintainer)