psydev balance changes PR

### This is a list of the changes to TD balance proposed for next playtest, by Psydev. The main, significant changes can be found here:
My pull request with all the changes can be found here: https://github.com/OpenRA/OpenRA/pull/5132

## Main Changes:
Nuke fixed (was broken and weak). Now it can destroy a Construction yard again, and possibly surrounding smaller buildings.
Obelisk of Light now fires continuously every 3.6 seconds instead of its unintentionally much longer delay. First shot only requires 2 second charge-up.
Tiberium now hurts veteran units
Guard tower nerfed vs. infantry and light vehicles. Does lower damage with higher spread.
All advanced towers have had their range reduced to 7.
SAM site range reduced to 8.
Cloak detection range of guard towers/turret reduced to 3. Cloak detection range of Advanced Guard Tower, Obelisk and Comm. Centers reduced to 5.
Mammoth Tank HP reduced 900 -> 800
Nod Artillery significantly buffed, especially vs. heavy armor and buildings.
Orca reload time reduced from 24 seconds to 12 sec. ROF slightly increased.
Orca buffed vs. Heavy armor
Flame Tank gets heavy armor, HP adjusted to 300. Buffed vs. light vehicles, cost reduced from $800 to 600.
Humvee/buggy buffed a bit vs. infantry.
Flamethrower infantry slowed to same speed as rifleman (making grenadier the only fast basic infantry unit)
APC nerfed a bit vs. light vehicles.
Sniper can now only fire at infantry
Tank HP buffs: Light tank raised from 300 HP -> 360. Medium tank raised from 400 HP -> 450.
All tank guns' damage vs. buildings increased from 75% -> 100%
Stealth tank damage vs. buildings increased from 50% -> 75%.
Guard tower cost increased from $500 -> $600
Grenadier range reduced from 5 to 4. Grenade speed lowered. Spread on explosion increased.
Air Strikes can destroy guard towers and turrets again but little else.
Probability of infantry avoiding being crushed raised from 50% to 67%
Tiberium damage reduced by a factor of 2 (not enough to kill usually)
Infantry more likely to walk through tiberium now, since its damage is lower
Refineries can now support 3 harvesters operating nearby instead of only 2. (unloading time was reduced, and in exchange, harvesters spend more time collecting tiberium.)
Refinery power consumption increased from 30 -> 50
Harvester cost reduced from $1200 -> $1000
Barracks/Hand of Nod cost increased from $300 -> $500.
Power plant cost increased from $300 -> $500 (adv. power plant also proportionately increased)
Low-power slowdown of Construction Yard's building queue made 1/2 instead of 1/3


##More Minor Changes

# Units:
Turret firing rate/damage tweaked slightly
Recon bike damage vs. wood increased from 50% -> 75%. Damage vs. infantry reduced from 65% -> 25%
All tank guns fire a bit faster, making them do more damage.
APC gets slightly slower firing rate and does less damage vs. light, but does a bit more damage vs. heavy armor.
Flamethrower does more damage vs. light vehicles, and slightly more vs. infantry; slightly less vs. heavy armor
MLRS does a bit more damage vs. buildings and infantry
MLRS spread increased from 15 -> 16
Chem Warrior damage vs. buildings reduced from 75% -> 50%.
Mammoth tank gun/missile damage balance adjusted. Missiles do not damage buildings quite as quickly now but Mammoth wastes fewer missiles now due to changes in timing of bursts.
Infantry walk at 90% speed on clear terrain instead of 100% (this was the old setting)
Chem warrior speed in tiberium is now the same as on open terrain
Vision range of Artillery, MLRS and Mobile SAM reduced from 10 -> 8.
Mobile SAM does a bit more damage
Mobile SAM range reduced from 10 -> 9
Stealth tank damage vs. buildings increased from 50% -> 75%.
Stealth Tank rotation speed increased from 8 -> 10.
Vision range buff: Buggy raised from 7 -> 8
Orca damage vs. air units reduced to 75% to make it even with the Apache.
Orca missile speed increased from 213 -> 298
Rotation speed of light tank turret raised from 5 -> 7, to match the tank's rotation speed
Rotation speed of light vehicles (bike, buggy, hum-vee) capped at 10.
Transport helicopter vision range extended to match orca / apache (from 8 -> 10).

# Other:
Ion Cannon spread slightly increased, to compensate for latest version doing less damage with spread.
Air strike does more damage vs. heavy armor.
A-10 is no longer targetable, since units would start chasing them after airstrikes until they left the map
SAM site's vision set to 8, to equal its range.
HPAD only requires refinery to build now. This is to allow for a conceivable early heli/orca opening.
Sight range has been reduced on some units, partly to accomodate changes in the game engine. For this reason, infantry detection of cloaked units at range=1 instead of 2.
Construction Yard power output reduced from 15 to 0.
Refinery sale value increased from $300 -> $500, to reflect change in harvester cost.
Refinery storage increased from 1500 -> 2000, and Silo storage reduced from 2400 -> 2000