(PUP-3003) Only include needed files in the MSI

Previously, we bundled all of puppet, facter, hiera, mcollective, and vendored ruby into the installer, which included many unneeded files, e.g. spec, acceptance, etc.

This PR ensures we only bundle needed files into the MSI.
    
With this change, the PE MSI size is reduced from 21MB to 18MB, FOSS is even less as it doesn't include mcollective. The installation directory (uncompressed) changes from 67MB to 55MB.

As a result of this change, the following file is added to the MSI (really it's been moved from puppet/ext/windows/eventlog):

    Only in Puppet Enterprise new/misc: puppetres.dll

And the following files are no longer included:

    C:\>diff -r "Puppet Enterprise" "Puppet Enterprise new"
    Only in Puppet Enterprise/facter: COMMITTERS.md
    Only in Puppet Enterprise/facter: CONTRIBUTING.md
    Only in Puppet Enterprise/facter: Gemfile
    Only in Puppet Enterprise/facter: README.md
    Only in Puppet Enterprise/facter: Rakefile
    Only in Puppet Enterprise/facter: acceptance
    Only in Puppet Enterprise/facter: documentation
    Only in Puppet Enterprise/facter: etc
    Only in Puppet Enterprise/facter: ext
    Only in Puppet Enterprise/facter: install.rb
    Only in Puppet Enterprise/facter: libexec
    Only in Puppet Enterprise/facter: man
    Only in Puppet Enterprise/facter: schema
    Only in Puppet Enterprise/facter: spec
    Only in Puppet Enterprise/facter: tasks
    Only in Puppet Enterprise/hiera: CONTRIBUTING.md
    Only in Puppet Enterprise/hiera: COPYING
    Only in Puppet Enterprise/hiera: Gemfile
    Only in Puppet Enterprise/hiera: README.md
    Only in Puppet Enterprise/hiera: Rakefile
    Only in Puppet Enterprise/hiera: acceptance_tests
    Only in Puppet Enterprise/hiera: docs
    Only in Puppet Enterprise/hiera: ext
    Only in Puppet Enterprise/hiera: install.rb
    Only in Puppet Enterprise/hiera: spec
    Only in Puppet Enterprise/hiera: tasks
    Only in Puppet Enterprise/mcollective: Gemfile
    Only in Puppet Enterprise/mcollective: README
    Only in Puppet Enterprise/mcollective: Rakefile
    Only in Puppet Enterprise/mcollective: etc
    Only in Puppet Enterprise/mcollective: ext
    Only in Puppet Enterprise/mcollective: install.rb
    Only in Puppet Enterprise/mcollective: mcollective.init
    Only in Puppet Enterprise/mcollective: spec
    Only in Puppet Enterprise/mcollective: website
    Only in Puppet Enterprise/puppet: COMMITTERS.md
    Only in Puppet Enterprise/puppet: CONTRIBUTING.md
    Only in Puppet Enterprise/puppet: Gemfile
    Only in Puppet Enterprise/puppet: README.md
    Only in Puppet Enterprise/puppet: Rakefile
    Only in Puppet Enterprise/puppet: acceptance
    Only in Puppet Enterprise/puppet: api
    Only in Puppet Enterprise/puppet: autotest
    Only in Puppet Enterprise/puppet: benchmarks
    Only in Puppet Enterprise/puppet: conf
    Only in Puppet Enterprise/puppet: docs
    Only in Puppet Enterprise/puppet: examples
    Only in Puppet Enterprise/puppet: ext
    Only in Puppet Enterprise/puppet: install.rb
    Only in Puppet Enterprise/puppet: man
    Only in Puppet Enterprise/puppet: spec
    Only in Puppet Enterprise/puppet: tasks
    Only in Puppet Enterprise/puppet: util
    Only in Puppet Enterprise/puppet: yardoc
    Only in Puppet Enterprise/sys: 1368-fix-scheduled-task-crash.patch
    Only in Puppet Enterprise/sys: CVE-2013-4363.txt
    Only in Puppet Enterprise/sys: PUP-1283-Get-description-failures-are-not-exceptional.patch
    Only in Puppet Enterprise/sys: PUP-2889-Rescue-LoadError-when-wevtapi.dll-can-t-be-loaded.patc
    Only in Puppet Enterprise/sys: README.md
    Only in Puppet Enterprise/sys: pe-1475-fix-cve-2013-4287.patch
    Only in Puppet Enterprise/sys: pe-1950-fix-cve-2013-4363.patch
This was intentional because we're no longer copying the `ext` directory from `downloads` to `stagedir`