Refactor the libvirt RPM daemon pieces
    
    There are a number of flaws with our packaging of the libvirtd
    daemon:
    
     - Installing 'libvirt' does not install 'qemu-kvm' or 'xen'
       etc which are required to actually run the hypervisor in
       question
     - Installing 'libvirt' pulls in the default configuration
       files which may not be wanted & cause problems if installed
       inside a guest
     - It is not possible to explicitly required all the peices
       required to manage a specific hypervisor
    
    This change takes the 'libvirt' RPM and and changes it thus
    
     - libvirt: just a virtual package with dep on libvirt-daemon,
       libvirt-daemon-config-network & libvirt-daemon-config-nwfilter
     - libvirt-daemon: the libvirt daemon and related pieces
     - libvirt-daemon-config-network: the default network config
     - libvirt-daemon-config-nwfilter: the network filter configs
     - libvirt-docs: the website HTML
    
    We then introduce some more virtual (empty) packages
    
     - libvirt-daemon-qemu: Deps on libvirt-daemon & 'qemu'
     - libvirt-daemon-kvm: Deps on libvirt-daemon & 'qemu-kvm'
     - libvirt-daemon-lxc: Deps on libvirt-daemon
     - libvirt-daemon-uml: Deps on libvirt-daemon
     - libvirt-daemon-xen: Deps on libvirt-daemon & 'xen'
    
     - libvirt-qemu: Deps on libvirt-daemon-qemu & libvirt-daemon-config-{network,nwfilter}
     - libvirt-kvm: Deps on libvirt-daemon-kvm & libvirt-daemon-config-{network,nwfilter}
     - libvirt-lxc: Deps on libvirt-daemon-lxc & libvirt-daemon-config-{network,nwfilter}
     - libvirt-uml: Deps on libvirt-daemon-uml & libvirt-daemon-config-{network,nwfilter}
     - libvirt-xen: Deps on libvirt-daemon-xen & libvirt-daemon-config-network
    
    My intent in the future is to turn on the driver modules by
    default, at which time 'libvirt-daemon' will cease to include
    any specific drivers, instead we'll get libvirt-daemon-driver-XXXX
    packages for each driver. The libvirt-daemon-XXX packages will
    then pull in each driver that they require.
    
    It is recommended that applications required a locally installed
    libvirtd daemon, use either 'Requires: libvirt-daemon-XXXX' or
    'Requires: libvirt-XXX' and *not* "Requires: libvirt-daemon"
    or 'Requires: libvirt'
    
    * libvirt.spec.in: Refactor RPMs
    * docs/packaging.html.in, docs/sitemap.html.in: Document
      new RPM split rationale