Adds Error Handling and Realtime Runtime Reviewal (#4679)

* Adds Error Handler

Adds a /world/Error proc to handle runtime errors. This proc replaces
the normal runtime logging behavior, providing the following
improvements:

- Adds timestamps to runtimes
- Pads or omits certain lines
- Continues logging runtimes after the 99th (with less info, as provided
by BYOND)
- Adds ckey and accurate xyz to usr info
- Continues including usr info after 19th runtime
- Silences spammy runtimes (by default, a runtime that occurs 10 times
in 10 minutes gets ignored for the next 10 minutes)

* Adds runtime viewer

Also fixes a minor mistake in the error handler

* Sanitizes HTML in Error Viewer

Also removes the stray return from the end of the error handler

* Prettifies Error Viewer

Now uses browser datum and some extra bits of formatting, inspired by
the changes made by @PJB3005

* Error Handling Improvements

- Skipped error counts now show up in the error viewer
- Proper runtimes caught by a process are now sent to the main error
handler
- The error handler and viewer can now handle a provided src, such as
one from a processing runtime
- Moved some info generation into helper procs

code/modules/admin/admin_verbs.dm

@@ -158,7 +158,8 @@ var/list/admin_verbs_debug = list(
 	/client/proc/cinematic,
 	/proc/machine_upgrade,
 	/client/proc/map_template_load,
-	/client/proc/map_template_upload
+	/client/proc/map_template_upload,
+	/client/proc/view_runtimes
 	)
 var/list/admin_verbs_possess = list(
 	/proc/possess,

code/modules/admin/topic.dm

@@ -2930,6 +2930,16 @@
 				Secrets(usr)
 				return 1
 
+	else if(href_list["viewruntime"])
+		var/datum/ErrorViewer/error_viewer = locate(href_list["viewruntime"])
+		if(!istype(error_viewer))
+			to_chat(usr, "<span class='warning'>That runtime viewer no longer exists.</span>")
+			return
+		if(href_list["viewruntime_backto"])
+			error_viewer.showTo(usr, locate(href_list["viewruntime_backto"]), href_list["viewruntime_linear"])
+		else
+			error_viewer.showTo(usr, null, href_list["viewruntime_linear"])
+
 /proc/admin_jump_link(var/atom/target, var/source)
 	if(!target) return
 	// The way admin jump links handle their src is weirdly inconsistent...

code/modules/admin/verbs/debug.dm

@@ -1234,3 +1234,13 @@ But you can call procs that are of type /mob/living/carbon/human/proc/ for that
 
 	// Clear the user's cache so they get resent.
 	usr.client.cache = list()
+
+/client/proc/view_runtimes()
+	set category = "Debug"
+	set name = "View Runtimes"
+	set desc = "Open the Runtime Viewer"
+
+	if(!check_rights(R_DEBUG))
+		return
+
+	error_cache.showTo(usr)