QoL update for janitors.

[Glamurio]

Janitors, like mechanics, are one of the few jobs that actually walk throughout the station a lot. While a lot of other jobs don't need a belt because they're usually close to their associated station, janitors would definitely benefit from having a dedicated belt with cleaning supplies. I could easily see their towel, a sponge, cleaner bottle and cleaner grenade or handheld vacuum being in there at round start. If there's a demand for it I'll gladly whip up a PR for this.