change various ResId classes that use conversion operator to OUString to
functions that return a OUString

drop various defines

drop unnecessary toString calls

Change-Id: Ibeccdf2b91a46a2ed5b4b74e6024e301a023bc92
Reviewed-on: https://gerrit.libreoffice.org/37817Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>