msi: record full build environment in MSI installer
    
    For proper compliance with the GPL and other licenses we need to be
    clear about exactly what toolchain and dependent packages we used in
    order to build the MSI installer we distribute.
    
    Historically we've done this by including a "deps.txt" file which
    provides a list of all the mingw{32,64}-* RPMs on the host system.
    
    This is not sufficient information, however, because the build system
    will in fact use various native packages too from the toolchain too,
    notably including any program run by "configure" which covers various
    shell utilities, and pkg-config, and then of course make & msitools
    itself.
    
    Rather than try to figure out which subset of host RPMs are used,
    just list every single host RPM that is installed.
    
    A key implication of this is that formal release builds should always
    be done in a pristine build root populated with the minimal content
    required for the build.
    
    Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>