Add a bit of ssh universal configuration.

This is intended to work with the `ssh-mgmt` scripts.  Maybe its
better to move this there?  Maybe not?

ssh/config

@@ -0,0 +1,14 @@
+CanonicalizeMaxDots 5
+CanonicalizeHostname yes
+CanonicalDomains nerdland.org
+
+Host gitea.* github.com
+	User git
+
+Host *.nerdland.org *.nerdland.it.cx
+	AddressFamily inet6
+
+Host *
+	IdentityFile ~/.ssh/id_%L-%h
+
+# vim: ft=sshconfig

startup_hooks/install.sh

@@ -72,3 +72,6 @@ echo "  signingKey = \"`hostname` Git\"" >> ~/.gitconfig
 echo "" >> ~/.gitconfig
 echo "[commit]" >> ~/.gitconfig
 echo "  gpgSign = true" >> ~/.gitconfig
+
+echo "Do not forget to add the following line at the top of your ssh config:"
+echo "Include ${CSHENV_LOCATION}/ssh/config"