Fixes regression #5948 where you could freely build any building by
canceling the production before deploying by restoring the currentItem
checks in the PlaceBuilding order to ensure that the production is still
valid.
This also implements support for a per-provider
cooldown between placing structures, allowing mods
with multiple structure queues to rate-limit
placement around a single provider.
An initial delay parameter is included to
support units that deploy into a base provider and
require an initial setup time (e.g. the Surveyor
unit from C&C TW).
The range and time restrictions are not applied to
walls as a balance choice.
outsourced into notifications.yaml
triggered with PlayNotification(...)
(v2: less redundant code for PlayVoice/Notifications)
added harvester under attack and battlecontrol terminated
