We now look for the existance of the room reservations 'bookings' table
prior to attempting to install the core bookings table and migrate it in
the same way the upstream plugin does before proceeding with installing
the core bookings tables.
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com> Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl> Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>