Add messages (paper, photos, cash) in bottles. (#85703)

## About The Pull Request
This PR adds a new persistent feature: message inside bottles. These are
basically glass bottles with inside a piece of paper, a photo or space
cash (no holocredits, and most bills rarely go over 1000 credits anyway)
from a previous round, which can be fished at the beach, or from the
relative fishing portals.

Each piece of written paper or photo that isn't map-loaded has a roughly
a 0.2% chance to be added to the message bottles database at the end of
the round. However, you can also manually toss a glass bottle with
inside a paper/photo/bill into the ocean (or a fishing portal generator
with the ocean/beach module loaded) for guaranteed results.

The bottles are removed from the database once fished up by the by,
unless tossed back into the ocean.

I've also offset a couple bottle sprites that weren't properly aligned
(for the message overlays).

TODO:
- [x] add a couple (20 prob or less) message bottle spawners to the
beach away mission or something.
- [x] add a few sounds for adding and removing the message from the
bottle. (pickup/drop sounds already handle that)
- [x] test it properly.

## Why It's Good For The Game
I think it'd be neat to have a way to send photos, snarky "seek grass"
messages, as well as the occasional financial aid to future players, and
furthermore, another thing to tie fishing to.

## Changelog

🆑
add: You can place papers, photos and cash bills (no holochips) inside
bottles and then toss them into the ocean (or fishing portal gen with
relative settings) with right-click, for others to fish them up on
future rounds.
/🆑

code/datums/json_database.dm

@@ -61,6 +61,16 @@
 /datum/json_database/proc/get_key(key)
 	return cached_data[key]
 
+/// Picks the data of a random key and then removes that key from the database.
+/// Since the list is no longer inside the database, you can mutate and use it as you like.
+/datum/json_database/proc/pick_and_take_key()
+	if(!length(cached_data))
+		return null
+	var/key = pick(cached_data)
+	. =  cached_data[key]
+	cached_data -= key
+	queue_save()
+
 /// Sets the data at the key to the value, and queues a save.
 /datum/json_database/proc/set_key(key, value)
 	cached_data[key] = value