fdo#82076 RTF import: handle footnote in table cell

Change-Id: I69def7936c320e93db5d4504922d52346caaf9cf
Let's have both switchHeaderFooter() calls in DocxExport::WriteHeaderFooter()

Change-Id: I051a2a74e0da44b8f13a21e052c35581159402f1
Avoid boost::optional<bool>

Change-Id: Idaacaf80098e59df47183741402c8664ba5ea631