dcache-chimera: Add interactive chimera shell

Adds an interactive shell for chimera. May also be used in non-interactive mode
with a command provided on the command line. In the latter form it supplants
the older chimera-cli utility.

Note that in some cases the argument order has changed compared to the
chimera-cli utility. The argument order now matches the order found in common
Posix utilities.

The chimera-cli utility should be documented as deprecated and eventually
removed from dCache.

The system-test populate script has been updated to use the new utility, which
avoids means the chimera skeleton can be created with a single invocation,
cutting down on the build time.

Target: trunk
Require-book: yes
Require-notes yes
Acked-by: Paul Millar <paul.millar@desy.de>
Acked-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Patch: http://rb.dcache.org/r/6423/