msi: Refactor to allow custom packages
* configure.ac: New package "gnupg-msi" to allow version independet packaging. * m4/gpg4win.m4 (GPG4WIN_BPKG_MSISRC): New macro for including wixlibs. * po/gpg4win-de.wxl, po/gpg4win-en.wxl: New strings. * src/Makefile.am (stamps/stamp-msi-base): New. * playground/install/gpg4win-$(VERSION).wixlib, gpg4win-$(VERSION).wxs: Moved around and modified. * src/WixUI_Gpg4win: Start some layout experiments. * src/gpg4win.mk.in (SETVARS_WINE, SETVARS_WINE_TWO_DOLLAR) (MSI_template): New templates to generate MSI targets. * stamps/stamp-versions-all-signed: Target to sign VERSION files. * src/make-msi.pl: Generate wxs files for customized configuration.
This enables the Gpg4win repo to create custom MSI packages
that contain a specific configuration, trusted root ca's etc.
and which might even contain a different GnuPG version as
we plan to branch between Gpg4win that contains GnuPG 2.3
and GnuPG Desktop which due to delays in evaluation etc. will
be more conservative and contain the GnuPG stable 2.2 branch.