Move echobot into /var/lib/echobot

cmdeploy/src/cmdeploy/__init__.py

@@ -477,6 +477,7 @@ def deploy_chatmail(config_path: Path) -> None:
         groups=["opendkim"],
         system=True,
     )
+    server.user(name="Create echobot user", user="echobot", system=True)
 
     server.shell(
         name="Fix file owner in /home/vmail",

cmdeploy/src/cmdeploy/service/echobot.service.f

@@ -7,6 +7,14 @@ Environment="PATH={remote_venv_dir}:$PATH"
 Restart=always
 RestartSec=30
 
+User=echobot
+Group=echobot
+
+# Create /var/lib/echobot
+StateDirectory=echobot
+
+WorkingDirectory=/var/lib/echobot
+
 # Apply security restrictions suggested by
 #   systemd-analyze security echobot.service
 CapabilityBoundingSet=