Unicode awareness Part 2 -- copytext() (#48512)

* Unicode support Part 2 -- copytext()

This is the transition of all copytext() calls to be unicode aware and also some nearby calls in the same functions. Most things are just replacing copytext() with copytext_char() as a terrible character limiter but a few others were slightly more involved.

I replaced a ton of
````
var/something = sanitize(input())
something = copytext(something, 1, MAX_MESSAGE_LEN)
````

with a single stripped_input() call. stripped_input() already calls html_encode(), trim(), and some other sanitization so there shouldn't be any major issues there.

This is still VERY rough btw; DNA is a mess, the status displays are complete ass, there's a copytext() in code\datums\shuttles.dm that I'm not sure what to do with, and I didn't touch anything in the tools folder. I haven't tested this much at all yet, I only got it to compile earlier this morning. There's also likely to be weird bugs until I get around to fixing length(), findtext(), and the rest of the string procs.

* Makes the code functional

* Assume color hex strings are always # followed by ascii.
Properly encodes and decodes the stuff in mob_helpers.dm which fixes some issues there.

* Removes ninjaspeak since it's unused

code/modules/admin/verbs/adminpm.dm

@@ -40,7 +40,7 @@
 		return
 	var/client/C
 	if(istext(whom))
-		if(cmptext(copytext(whom,1,2),"@"))
+		if(whom[1] == "@")
 			whom = findStealthKey(whom)
 		C = GLOB.directory[whom]
 	else if(istype(whom, /client))
@@ -75,7 +75,7 @@
 	var/client/recipient
 	var/external = 0
 	if(istext(whom))
-		if(cmptext(copytext(whom,1,2),"@"))
+		if(whom[1] == "@")
 			whom = findStealthKey(whom)
 		if(whom == "IRCKEY")
 			external = 1
@@ -132,7 +132,7 @@
 
 	//clean the message if it's not sent by a high-rank admin
 	if(!check_rights(R_SERVER|R_DEBUG,0)||external)//no sending html to the poor bots
-		msg = trim(sanitize(copytext(msg,1,MAX_MESSAGE_LEN)))
+		msg = trim(sanitize(msg), MAX_MESSAGE_LEN)
 		if(!msg)
 			return
 
@@ -293,7 +293,7 @@
 	if(!stealthkey)
 		stealthkey = GenTgsStealthKey()
 
-	msg = sanitize(copytext(msg,1,MAX_MESSAGE_LEN))
+	msg = sanitize(copytext_char(msg, 1, MAX_MESSAGE_LEN))
 	if(!msg)
 		return "Error: No message"