This patch registers vnd.libreoffice.command unconditionally,
and also registerd ms-word, ms-excel, ms-visio and ms-powerpoint
handlers according to SELECT_WORD, SELECT_EXCEL, SELECT_VISIO, and
SELECT_POWERPOINT properties (that are set in FileTypeDialog).

This allows to use these URIs in e.g. SharePoint WebDAV integration

Change-Id: I3231a15196858da77f1784a47f86f1729a6044bb
Reviewed-on: https://gerrit.libreoffice.org/29988Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>