Putting OME-XML formats docs into ome-docs repo (rebased onto develop)



This is the same as gh-296 but rebased onto develop.

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Addresses https://trac.openmicroscopy.org.uk/ome/ticket/10099

Once Seb has set up the build, these pages will be testable under
http://www.openmicroscopy.org/site/support/formats-staging/