Implement more serverside utility fields on tankdefinitions

[Nul-led]

Why:

Fun?

Summarize what's being changed (include any screenshots, code, or other media if available):

added fields (and logic):

• barrel/distance (y-offset aka distance of barrel from body)
• barrel/color (color override)
• tank/flags/displayAsStar
• tank/flags/displayAsTrapezoid
• tank/widthRatio (if the body is a rect, this can be used to modify the ratio of size to width)
• tank/colorOverride (color override; rules: only applied on setTank, stores cached color)
• tank/baseSizeOverride

Confirm the following:

• [x] I have tested these changes (by compiling, running, and playing) and have seen no unintended differences in gameplay