Moves the part of the code handling the holder things on scooped up snacking to where the actual snacking happens, and also clears and deletes the holder afterward.
Also contains checks to make sure any undeclared stowaways in holder contents also get eaten (or dumped on the ground if that somehow fails) instead of getting deleted with the holder. Probably fixes a lag or garbage collection jank bug that sometimes makes the holder dump the prey back on ground after they've already been eaten, and also fixes the thing with the holder item still lingering in hand for the entire process cycle duration after the prey has already been eaten.
Also makes holders use Entered/Exited to do their things with the contained mob to make them function more reliably. (now makes sure only one mob can enter a holder, and now also clears the held_mob var and returns the held mob's transform appearance back to the mob without requiring the ground dump proc, which probably also fixes the thing with eaten held mobs sometimes getting released with messed up scaling etc)
Tested working nicely.
This adds throw_alert() and /obj/screen/alert, a system that allows you
to do custom hud alerts for any variety of things from "You're too
cold!" to mecha status indicators for the pilot.
There's quite a few things that actually got replaced; the
fire/oxy/tox/co2 alerts are all now just alerts, as is nutrition. The
xenochimera feral indicator would probably be a good candidate for
conversion, but I didn't touch it in this PR. There's also a number of
new alerts, such as blindness, highness, legcuffed, buckled, handcuffed,
and probably some more I missed; read code/_onclick/hud/alert.dm and see
for yourself!
Additionally, a number of tweaks have been done to resisting code, to
make it so that there's an indicator when you're buckled or handcuffed,
and can just click the alert to start resisting. This includes a
refactor that combines the logic for lockers, holders, micros
escaping from shoes, and struggling in a gut all into one proc, called
container_resist(). This means that vore bellies actually no longer need
the resist override, but it's been left in place just in case someone
finds something else they want to use it for.
Also, the health and internals indicator got moved down one tile each.
Needed room for the alerts. If we add the oxygen tank action buttons
from /tg/ and remove the internals indicator, the health indicator can
go back where it was originally.
