Creates update_name and update_desc
Creates the wrapper proc update_appearance to batch update_name, update_desc, and update_icon together
Less non-icon handling code in update_icon and friends
Signal hooks for things that want to change names and descriptions
99%+ of the changes in this are just from switching everything over to update_appearance from update_icon
## About The Pull Request
fixes a pretty bad exploit with foam darts
## Why It's Good For The Game
- Modify a dart with a pen, giving it 5 damage
- Target someone's mouth (or a monkeyman)
- Fire
- Firing sequence for handle_suicide multiplies damage by 5 on the projectile instance
- Dropped projectile has 25
- Repeat 1 more time for 125 instacrit dart, or another time after that for 600 instakill dart
all discovery credits go to @necromanceranne, this was brought to my attention
Projectiles are assigned the ability to try embedding by the presence of a shrapnel_type variable being set on them, whether or not they actually have a set of embedding stats in their embedding var. By default, children of /obj/projectile/bullet have a shrapnel type set to a generic embedded bullet item, including things like foam darts and lollypop projectiles which shouldn't be able to embed (and certainly not embed as a bullet). While they had their embedding vars set to null, they still had their shrapnel_type set to the embedded bullet type, meaning shooting a person with a dart gun or whatever would leave a failed shrapnel item on the ground where they weren't supposed to.
This fixes that by requiring both a defined shrapnel_type AND a defined embedding var for the embedding stats. Any projectiles without both won't be able to try embedding. I also manually put 'shrapnel_type = null' on any bullet subtypes with embedding = null just to be safe and for consistency.
