Formatter: add TableFormatter class for more human readable and shell parsable output

Signed-off-by: Andreas Peters <andreas.joachim.peters@cern.ch>
Formatting

Signed-off-by: Andreas Peters <andreas.joachim.peters@cern.ch>
librados: adding RadosWhereis class to provide an object location API

Signed-off-by: Andreas Peters <andreas.joachim.peters@cern.ch>
rados tool: adding 'whereis [--dns]' command and '--format table[-kv]' for table output format

Signed-off-by: Andreas Peters <andreas.joachim.peters@cern.ch>