[PM] Adds support for logstash

[PM] Modifies Dockerfile to optimize use of cache
[MON] Fixes py3 compatibility issue in Aodh notifier
[MON] Removes use of sudo in vrops webservice script

Signed-off-by: diazb <bdiaz@whitestack.com>
Change-Id: I93b4bb57f49238a57067cf035509c3e62da5ec2a
7 files changed