Added shard performance tests (shard_perf_test.py and shard_multi_test.sh)
Cleaned up help text for inventory crawler

Change-Id: I6b5791155e082e6267ebaf9aa3555ccb59f32677
Signed-off-by: Jan Medved <jmedved@cisco.com>
(cherry picked from commit 5de8c834131e0ae94e0d5f1ec50a7519c529e58c)