Add enforcement for foreign key contraints with sqlite

Fixes bug 1171732

When creating an engine the called can indicate whether or
not to enforce the constraints for sqlite.

Change-Id: I1d5820376f60388c084afea500f807cd25541800
Avoid calling sudo in install_venv_common.py.

Updates our common venv installation routine so that it no longer
attempts to automatically install missing RPM packages via sudo
and instead just prints an error message and dies.

The primary motivation here was to avoid sudo altogether since
some people would rather not have the test suite run these sorts
of systems admin commands for them.

Change-Id: I350e5421a4dd3094217270d39547acaea0aeda3b
Add middleware to limit size of HTTP requests.

Adds a new RequestBodySizeLimiter middleware to guard against
really large HTTP requests. The default max request size is 112k
although this limit is configurable via the 'max_request_body_size'
config parameter.

Change-Id: I76248feed5c77f678b8a43f364d4f1e0794ab910
Add missing LICENSE file

Don't we need one?

Change-Id: I2b8cdf40dd9493db1f497893939f897c06337c04
Add a MAINTAINERS file

Following on from discussions at the summit, add a file which explains
the idea of oslo-core being a group of generalists and that each API
in the incubator should have a specialist maintainer.

I've made a quick stab at capturing the status of APIs where its most
obvious. I'm thinking we let people submit changes to add themselves
to the file so they're on record saying "I'll maintain this".

Change-Id: I5e67f94dc77f14849dea425dec51896fed0d07ef
Merge "Add missing LICENSE file"
Merge "Add enforcement for foreign key contraints with sqlite"
Merge "Add middleware to limit size of HTTP requests."
Merge "Avoid calling sudo in install_venv_common.py."