launch_daemon: Initialize /tmp & /var/shared_memory, clock.

* Added initializing /tmp & /var/shared_memory to the launch_daemon.
* Moved clockconfig.cpp code into the launch_daemon.
* This follows systemd design; since those jobs are fixed, it doesn't
  matter where you maintain them.
* The init jobs are BJobs, but the JobQueue is only used for that
  one use for now. At a later time, I intend to put the job launching
  in there, as well. BJob allows to represent the dependencies already.

build/jam/images/definitions/minimum

@@ -3,8 +3,7 @@
 SYSTEM_BIN = [ FFilterByBuildFeatures
 	addattr alert arp
 	bc beep bfsinfo
-	catattr checkfs checkitout chop clear
-	clockconfig cmp collectcatkeys compress copyattr
+	catattr checkfs checkitout chop clear cmp collectcatkeys compress copyattr
 	dc desklink df diff diff3 diskimage draggers
 	driveinfo dstcheck dumpcatalog
 	eject error