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
