Adds Internet admin midi (#30457)

* Adds Internet admin midi

* Moves global regex into proc (shell_url_scrub)

* Moves shelleo to world
Adds quotes around the command in shelleo, to encapsulate it

* Admins can stop playing web sounds

* Revised internet midi extension order
Moved m4a to least preferred,
as it can potentially carry non-aac or non-mpeg-3 audio

* Kills \n in web sound

* play_web_sound availability based on config

* play web sound and shelleo tweaks

istypeless for in play web sound & readability parenthesis around binary AND
add return index defines for shelleo proc

* Security fix for play web sound

code/__HELPERS/shell.dm

@@ -0,0 +1,57 @@
+//Runs the command in the system's shell, returns a list of (error code, stdout, stderr)
+
+#define SHELLEO_NAME "data/shelleo."
+#define SHELLEO_ERR ".err"
+#define SHELLEO_OUT ".out"
+/world/proc/shelleo(command)
+	var/static/list/shelleo_ids = list()
+	var/stdout = ""
+	var/stderr = ""
+	var/errorcode = 1
+	var/shelleo_id
+	var/out_file = ""
+	var/err_file = ""
+	var/static/list/interpreters = list("[MS_WINDOWS]" = "cmd /c", "[UNIX]" = "sh -c")
+	var/interpreter = interpreters["[world.system_type]"]
+	if(interpreter)
+		for(var/seo_id in shelleo_ids)
+			if(!shelleo_ids[seo_id])
+				shelleo_ids[seo_id] = TRUE
+				shelleo_id = "[seo_id]"
+				break
+		if(!shelleo_id)
+			shelleo_id = "[shelleo_ids.len + 1]"
+			shelleo_ids += shelleo_id
+			shelleo_ids[shelleo_id] = TRUE
+		out_file = "[SHELLEO_NAME][shelleo_id][SHELLEO_OUT]"
+		err_file = "[SHELLEO_NAME][shelleo_id][SHELLEO_ERR]"
+		errorcode = shell("[interpreter] \"[command]\" > [out_file] 2> [err_file]")
+		if(fexists(out_file))
+			stdout = file2text(out_file)
+			fdel(out_file)
+		if(fexists(err_file))
+			stderr = file2text(err_file)
+			fdel(err_file)
+		shelleo_ids[shelleo_id] = FALSE
+	else
+		CRASH("Operating System: [world.system_type] not supported") // If you encounter this error, you are encouraged to update this proc with support for the new operating system
+	. = list(errorcode, stdout, stderr)
+#undef SHELLEO_NAME
+#undef SHELLEO_ERR
+#undef SHELLEO_OUT
+
+/proc/shell_url_scrub(url)
+	var/static/regex/bad_chars_regex = regex("\[^#%&./:=?\\w]*", "g")
+	var/scrubbed_url = ""
+	var/bad_match = ""
+	var/last_good = 1
+	var/bad_chars = 1
+	do
+		bad_chars = bad_chars_regex.Find(url)
+		scrubbed_url += copytext(url, last_good, bad_chars)
+		if(bad_chars)
+			bad_match = url_encode(bad_chars_regex.match)
+			scrubbed_url += bad_match
+			last_good = bad_chars + length(bad_match)
+	while(bad_chars)
+	. = scrubbed_url