Verify user/project ID for alarm created by non-admin user

Fixes bug 1297677

Previously, when a non-admin user created an alarm on behalf of
another user, the ownership of the alarm silently reverted to the
requestor's identity.

Now, we check for this case and fail with 401 Not Authorized when
a non-admin user attempts to create an alarm explicitly associated
with another identity.

Change-Id: I8f372b1523012990b8f1d48b03cf9ed9cef65c60
SSL errors thrown with Postgres on multi workers

database connections were made on service initialisation and not
on process start. this led to all processes of a service sharing
the same connection. in this patch, we create unique
dispatch_manager to handle a different engine for each process.

we keep default to a single worker as schema needs to be updated
to avoid possible race/deadlock conditions

Closes-Bug: #1298073
Change-Id: I2ad05e2085c0c0f78653c6354d301d18b8dee121
Merge "Verify user/project ID for alarm created by non-admin user"