Add new target category, add it to auto trajectory units

[SethDGamre]

I noticed that groundscouts aren't the only units fast enough to give auto trajectory units a hard time. This PR creates a new target category for units that are faster than a rez bot and gives it to those auto trajectory units for starters.

https://youtu.be/qe8-Pg3lzwg

Testing steps:

Spawn any of the units changed in this PR and test it on various targets greater than and less than 78 movement speed and that moves around on the surface -- this is what qualifies them for FASTSURFACE category.

[S3KCentrifugal]

For reference the BARb AI configures target categories in link below. Don't forget to update the AI behavior when adding armordefs or categories.

Beyond-All-Reason/luarules/configs/BARb/stable/script/common.as

Line 13 in 3bc52b7

SCategoryInfo InitCategories()

[SethDGamre]

Beyond-All-Reason/luarules/configs/BARb/stable/script/common.as

The categories listed there seem to be for identifying the movement type of the unit - land, sea, air. The new category is applied in addition to those and unless there's a portion of the AI code that needs to know if a unit moves fast or not, this isn't yet useful there.

[kroIya]

Basing it exclusively off of speed does not account for how maneuverable a unit is.
corpship is fast at 82.5 speed, but is large and turns slowly, and is an easy target to hit. Navy is commonly defended against with static artillery

[SethDGamre]

Basing it exclusively off of speed does not account for how maneuverable a unit is. corpship is fast at 82.5 speed, but is large and turns slowly, and is an easy target to hit. Navy is commonly defended against with static artillery

Maneuverability is a better metric. Any insights into how I can filter by manueverability and which units would be slippery?

Perhaps this category should become SLIPPERYSURFACE

[SethDGamre]

now the target category is used only for high trajectory which would really struggle to hit the quick units.