This is the final fix for tdf#41542 - enabling the UI to adjust the
padding without requiring an enabled border line.

Because almost every document edited by LO5.3 will gain the setting
ALLOW_PADDING_WITHOUT_BORDERS = false, it cannot be kept as a
preventative compatibility setting. Otherwise any document edited
in 5.3 would act differently from any other document - not being
allowed to modify borderless padding for frames, even in 5.4+.
That would be a very confusing corner-case that is best avoided,
so removing all compatibility code (which currently has no use).

So, if an AllowPaddingWithoutBorders=false compatibility
situation is ever required in the future, do not
resurrect the name ALLOW_PADDING_WITHOUT_BORDRES. Additionally, code
will also be needed to send the compatibility setting for
each type of border (page, paragraph, character, header, frames, image).
See commit f013d4a1 as an example
of how to implement that for frames.

This commit means there is a lot of dead code now (m_bBorderDist and
mbAllowPaddingWithoutBorders are always true). LO5.7 seems like a good
target to clean that up - to allow time to easily fix any regressions.

Change-Id: I2d2091fa34f8b178a59347b35a81c944c9b24ed7
Reviewed-on: https://gerrit.libreoffice.org/31105Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Justin Luth <justin_luth@sil.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>