[MIRROR] Add development override configuration system [MDB IGNORE] (#17752)

* Add development override configuration system (#71427)

Config system will now load dev_overrides.txt automatically if it
exists, but this file is in gitignore. I want to use this for
configuring SQL and such easier.

* Add development override configuration system

Co-authored-by: Mothblocks <35135081+Mothblocks@users.noreply.github.com>

.gitignore

@@ -1,5 +1,8 @@
 ###Files and folders specified here will never be tracked.
 
+# Local overrides--you can use this to change the config for your dev environment (like setting up SQL) without worrying about committing it
+/config/dev_overrides.txt
+
 #Ignore everything in datafolder and subdirectories
 /data/**/*
 /tmp/**/*

code/controllers/configuration/configuration.dm

@@ -84,6 +84,8 @@
 				for(var/J in legacy_configs)
 					LoadEntries(J)
 				break
+	if (fexists("[directory]/dev_overrides.txt"))
+		LoadEntries("dev_overrides.txt")
 	loadmaplist(CONFIG_MAPS_FILE)
 	LoadMOTD()
 	LoadPolicy()

config/dev_overrides_readme.txt

@@ -0,0 +1,5 @@
+# Make a new file named dev_overrides.txt in order to be able to add your own configuration
+# without worrying about committing. These are applied after config.txt.
+# You do not need this if you are a server operator! You should instead use the $include system.
+
+#STATIONNAME My Dev World