Remove Hard, add events to Production Disruption

[JovialFeline]

• Removed the extra Hard difficulty. Its addition was a side effect from Added localisation support to difficulty dropdown #20585, and it played the same as Easy because the Tesla Coil and vehicles added for Normal were skipped.
• Fixed a missing call to FinishTimer. The mission text no longer freezes with 0:01 remaining.
• Changed Chrono Tanks to appear with the full chronoshift effect.
• Added the usual campaign bots to the Soviets. They're now less willing to stand idle while being shot.
• Changed the start speech to "Mission timer initialised."
• Changed the player's low power notification to reduce nagging from the southern Radar Dome's capture. The notification is muted until a USSR structure is captured. USSR owns the first two Flame Towers and everything north of the bridge except the Sub Pen.
• Added a warning reveal to the first Flame Towers. This is skipped if they have already been revealed by the power cut.
  • There is a similar (bugged) reveal in the original mission, though it was coupled with a bridge explosion.
• Nudged a V2 Rocket Launcher away from a bomber's path.
• Split some of the script into sub-functions, for a hopefully smoother read.

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Added some stuff that was in the original mission:

• A powering down sound plays when the coil power is knocked out.
• The Forward Command's death triggers a USSR fire sale and more Allied paratroopers. The sale does not include the Sub Pen, which is owned by BadGuy.
• Removal (or capture) of both SAM Sites triggers an Allied bombing run.

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Notes on some original behavior I've skipped:

• Destruction of one Flame Tower is enough to reveal the beachside Radar Dome.

• The built submarine waits a few moments to guard the area before its move to the exit. "A few moments" in this case is a whopping ~39 seconds.

  • Its health is also trimmed to half the usual, and the original rules make its light armor a bit weaker to AP missiles (and infantry rifles).

• Once the first Flame Towers are approached or the two southern power plants are destroyed, a soldier moves forward to demolish the bridge. This is done with a reveal.

  • That trigger (BRDG) seems bugged. Waypoint 25, the out-of-bounds submarine goal, is used for the reveal instead of waypoint 5 at the bridge.

  • ORA truck nukes can easily reach him, and I gather from the Add Aftermath mission Production Disruption #18230 discussion that more attention toward the bridge isn't wanted anyway.