Doxygen: Update doxygen hosting URL

Signed-off-by: Vicente Adolfo Bolea Sanchez <vicente.bolea@kitware.com>
5 jobs for fix-doxygen-docs
Status Name Job ID Coverage
  External
passed cdash-buildbot

passed vtk-m-dragnipur-osx-shared-debug+32bit_ids+64bit_coords+clang+tbb

00:01:15

passed vtk-m-dragnipur-osx-static-release+64bit_coords+clang+tbb

00:00:16

passed vtk-m-osheim-windows-shared-debug+ninja-vs-2017+tbb

00:06:10

passed vtk-m-osheim-windows-static-release+ninja-vs-2017+tbb

00:00:46