tdf#152266 add an infobar with indicators for macro-like content in doc

Show "macros" and "events" for now if we know that are present so
they can be investigated by the user. There are other things which
could potentially be added in the future.

Change-Id: I981ee7a8e22791cd15405894f30fee659ba0b7ba
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/143897
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>