`bitcoind` can take a long time to flush its db cache to disk upon
shutdown. Most init files send a `SIGKILL` after a timeout of 1 minute,
causing unclean shutdowns and triggering a long "Rolling forward" at the
next startup. Increasing this timeout to 10 minutes should reduce how
often this occurs, especially during IBD.
fixup! Set ProtectHome in systemd service file
The bitcoin user needs read access to the configuration file, but write
access is not needed. It is not considered best practice to make
configuration directories and files owned by the services reading them.
Rather than making the config dir world-readable, which potentially
leaks RPC credentials, the group of the directory is changed to the one
the service is executed as.
The phrasing seemed to indicate that the options specified in
ExecStart= could not be specified in the config file, necessitating
their inclusion in the service file. However, the options in the
config file simply get overridden by any specified in ExecStart=.