(maint) Extract package installation step as an acceptance lib

Pulls the code that was installing packages on acceptance hosts into an
acceptance/lib helper library.
(maint) Windows acceptance configuration

foss-win-2003r2-ruby-193.yaml has a working configuration with a vcloud
rhel master and the old static win2003r2-ruby-193 vm.

win2008.yaml is an experimental configuration with vcloud win2008 64bit,
but it has problems with the cygwin curl on 64bit platforms always
including header info: http://permalink.gmane.org/gmane.os.cygwin/141462
This makes it difficult to install packages through cygwin the way
beaker is expecting to be able to.
(maint) Acceptance harness Rakefile updated to use Beaker