ssh: config: externalize host configuration

Even though it may not be critical to have usernames, hostnames and the
respective ssh ports out in the open as they usually aren't secret, it
should still be avoided.

ssh/config

@@ -3,44 +3,10 @@
 Host *
 	AddKeysToAgent confirm
 
-Host 0?? 0???
-	HostName faui%h.informatik.uni-erlangen.de
-	ForwardAgent yes
+# Include external config if available
+Include conf.d/*
 
-Host faui0? faui0?? faui0???
-	HostName %h.informatik.uni-erlangen.de
-	ForwardAgent yes
-
-Host man? man?? big?
-	HostName faui49%h.informatik.uni-erlangen.de
-	ProxyJump ty28wuqu@i4lab1.informatik.uni-erlangen.de
-
-Match Host faui*
-	User ty28wuqu
-
-Host ircbox
-	HostName ircbox.informatik.uni-erlangen.de
-	User ty28wuqu
-
-Host irc
-	HostName tpreisner.de
-	User weechat
-
-Host server
-	HostName tpreisner.de
-	User root
-
-Host steep
-	Hostname steep.cs.fau.de
-	User preisi
-	Port 17
-
-Host pi
-	HostName wg.tpreisner.de
-	# dynamic ip behind hostname would cause warnings
-	CheckHostIP no
-
-# use if they havent been defined yet:
+# Use if they havent been defined yet:
 Host *
 	Compression yes
 	ForwardAgent no