Bacterial Contamination and Infections

[r3ndd]

This is a plan to add simple bacterial contamination to the station, separate from but compatible with and complimenting some proposed virology systems such as #332 . All percentages/probabilities I provided are just for illustrative purposes and may need to be adjusted for balancing. I haven't contributed to the SS14 codebase before, but I reviewed the codebase and relevant files and this looks fairly straightforward to implement using a new event system.

[NoElkaTheGod]

Cool, but will there be a super-duper resistant bacteria? :godo: