set the cwd in the service file

otherwise it wouldn't find the codemirror files

go/linguaevalia/etc/linguaevalia.service

User=nobody
Group=nobody
ExecStart=/home/lu/k/lp/go/linguaevalia/linguaevalia server -p 8042
WorkingDirectory=/home/lu/k/lp/go/linguaevalia
[Install]
WantedBy=multi-user.target