Replace busybox syslogd with logbookd

Use logbookd to replace the busybox in-memory logger. The default configuration of logbookd still logs in-memory but writes out the log on shutdown or manual trigger.

The logread command is also replaced by a drop-in replacement for the busybox tool.

To test

Install thir MR with mrtest and enable the logbookd service, then disable the syslogd service. This replaces the logread command to give neater log output