feat(environment.d): configure systemd ssh-agent if available

.environment.d/ssh_agent.env

@@ -0,0 +1,4 @@
+if [[ -e ${XDG_CONFIG_HOME:-$HOME/.config}/systemd/user/default.target.wants/ssh-agent.service ]]
+then
+  SSH_AUTH_SOCK=$XDG_RUNTIME_DIR/ssh-agent.socket
+fi

.github/README.md

@@ -39,6 +39,7 @@ git --work-tree=$HOME --git-dir=$HOME/.dotgit checkout master
 - fix the umask
 - Vim put the Yaml indent Stuff in a proper filetype detection script (ftplugin?)
 - Vim also add cfn filetype for cfn-lint
+- enable user systemd units during install (for example the sysd ssh-agent)
 
 ## Echos to be replaced by msg()
 - fuck error msg