Xenofauna Tech equipment update.

[MistakeNot4892]

• Resprited the tranq rifle and tranq pistol to be grey and blue instead of black and yellow.
• Set tranqs to use a different projectile icon and sound (thanks @Spookerton) to further distinguish them from phase guns.
• Added purple-marked versions of the non-modular explorer suit and base explorer uniform for xenofauna techs.
• Added basic animal taggers, with persistence code commented out for a future PR.
• Allowed GPS to filter based on a category var, currently only used by xenofauna tags.
• Added some supporting vars for future non-station persistence.