Implement stack-locking for multi-engine support

Implements a distributed stack lock using the database to avoid race
conditions when multiple engines are deployed.

Blueprint multiple-engines

Change-Id: I7fba8808d8a4efbe7fd8fdff94fd9a53f3841c8b
Add property doc strings for S3 bucket

Change-Id: I508a6ea45748e366c4cc4f6f47f200ac4145cee1
Closes-bug: #1224148
Revert "Implement stack-locking for multi-engine support"

This is a short term backout until it gets fixed.

This reverts commit c30530f12663302869a8f2edf979e8a8bd33ed2d.
Closes-bug: #1250797

Change-Id: Ide1dc4a9d1469dee033e8bc08d8ab4da96f79fc0
Merge "Revert "Implement stack-locking for multi-engine support""