Adds a Flare Gun

[KingOfThePing]

This PR adds a flare gun. It has been modified and tweaked to fit into Aurora. Some tasks still remain, as well as testing:

• [ ] restrict allowed ammo type (only flash and new flare ammo)
• [x] implement flare ammo
• [ ] implement consequences using an unallowed ammo type
• [ ] implement illumination mechanics of flare ammo

The flare gun is intended to mark your own position during expeditions (people will be notified of a bright light in chat) or to illuminate dark areas. Almost forgot, original PR: https://github.com/Baystation12/Baystation12/pull/28778

Asset Licenses

The following assets that have not been created by myself are included in this PR:

Path	Original Author	License
gunshot_thump.ogg	LeMudCrab (FreeSounds.org)	CC0
/icons/obj/contained_items/weapons/flare_gun.dmi (base sprite)	Toriate (Baystation12)	GPL3
/icons/obj/contained_items/weapons/flare_gun.dmi (in-hand sprites)	TheLancer (Aurorastation)	GPL3

[KingOfThePing]

!wip

[KingOfThePing]

I have to think about a new way to do this since my original idea does not work at all. This WILL return.