Found with bin/find-unneeded-includes
Only removal proposals are dealt with here.
Cleaned subdirs: sidebar, slideshow, slidesorter, table, unoidl

Change-Id: Iae3b8b2581b6a07dad24b4d2d59ffae24f882fe3
Reviewed-on: https://gerrit.libreoffice.org/65913
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>