MSWord has two choices for footnotes - at page-end or page-bottom.
LO has different choices for footnotes - at document-end or page-bottom.
Since document-end footnotes act like endnotes,
convert those footnotes into endnotes during DOC/DOCX/RTF export.

No matter what happens in this situation, some compromises have to be
made. The main compromise now is that the anchor numbering for endnotes
defaults to i,ii,iii while footnotes are 1,2,3. The conversion
obviously will switch to endnote style. This is user adjustable of course
and will be retained on following round-trips. Also the (footnote)
paragraph style is retained, but future endnotes will use a potentially
different endnote paragraph style.

Remedying those perceived deficiency is left as an exercise
for the motivated reader, who of course will
take into account the possibility of both endnotes and
chapter-end footnotes existing in the same document...

The unit tests' primary purpose is to ensure that footnotes following
down the endnote export path don't cause LO to crash.

Change-Id: I219d499df7981a14f824a664b15051ad10ff6642
Reviewed-on: https://gerrit.libreoffice.org/38634Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Justin Luth <justin_luth@sil.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>