With this change ResolveGraphicObjectURLFromBase64 and
ResolveGraphicObjectURL became unused and are also removed with
this commit.

Change-Id: I45428a4e47f0e8800f18c1fdba007293dfcb53f4
Reviewed-on: https://gerrit.libreoffice.org/51043Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>