Increase timeout to avoid killing the core during shutdown (#45029)

Stopping the core goes through several stages, which can take up to
120s, 60s and 30s respectively. However, if shutdown is taking longer
than 60s overall, s6 isn't patient and kills the core:
Jan 10 23:56:58 homeassistant eb034fca9c7d[407]: s6-svwait: fatal: timed out
Jan 10 23:56:58 homeassistant eb034fca9c7d[407]: [s6-finish] sending all processes the TERM signal.
Jan 10 23:57:01 homeassistant eb034fca9c7d[407]: [s6-finish] sending all processes the KILL signal and exiting.

This is most of the time not a problem since shutdown is quicker than
that.

However, increasing the timeout is especialy useful to debug cases when
an event is hanging, since the core will point it out after its timeout
elapsed.

Set the timeout to 220s, which is all core timeouts plus 10s grace time.

Dockerfile

@@ -1,8 +1,9 @@
 ARG BUILD_FROM
 FROM ${BUILD_FROM}
 
+# Synchronize with homeassistant/core.py:async_stop
 ENV \
-    S6_SERVICES_GRACETIME=60000
+    S6_SERVICES_GRACETIME=220000
 
 WORKDIR /usr/src