LibreOffice.natvis: fix BigPrtArray visualiser.

Also visualisers for uno_Any and SwNode are tweaked.
Visualisers for uno::Reference, rtl::Reference and VclPtr added.
SwFrameFormats visualiser reimplemented to follow implementation
of boost::multi_index_container.
Minor reformatting.

Change-Id: I24ccb8bfccd7f7514697ca3f36490672ad549aef
Reviewed-on: https://gerrit.libreoffice.org/40466Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>