Add Sentry DSN option to service files

bin/install-service-files.py

 KillSignal=SIGINT
 Type=notify
 NotifyAccess=all
+Environment=SENTRY_DSN={os.environ.get("SENTRY_DSN")}
 
 [Install]
 WantedBy=default.target
 
 [Service]
 ExecStart={piket_client_path}
+Environment=SENTRY_DSN={os.environ.get("SENTRY_DSN")}
 
 [Install]
 WantedBy=graphical.target