Add details to HttpException string

Without this change:

    400 Client Error: Bad Request

With this change, the much more useful:

    HttpException: 400 Client Error: Bad Request, Validation error: instance 'flavorRef' is a required property

Change-Id: Iaa63969e327532c02d72999efcbee42aa0d381d3
Add image resource to v2 images api

Adds the image resource for images v2 api, which consists of image
metadata, and provides access to the associated sub-resources such
as the image payload itself.

Change-Id: I9431562ed07e4bb2e01cec0769793f4302cf816b
Support regionless/global services

In order to not fail while reading service catalogs which contain
services which are configured to be global, meaning without a configured
region, parse and normalize the catalog without mentioning a region for
that service.

Change-Id: Idf84dc0f44fecb41845bb8d57617d10cc6e0d77d
Prepare for documentation of Resources

Add a section for where Resource classes will show up in the docs and
enter two skeleton pages for how this will look. Later changes will
cover the actual member-level documentation of the Resource classes for
each service, along with their addition to the TOC.

This additionally sets autodoc_member_order globally to "bysource",
meaning it'll order the rendered member documentation in the order it
was written. The default of alphabetical order by what shows up in
__dir__ is not as helpful or as readable as how we've organized the code.

Change-Id: Ifcd7cd81ba55ecb429c50680a926d4f8a44ca9a3
Merge "Add details to HttpException string"
Merge "Add image resource to v2 images api"
Merge "Support regionless/global services"
compute/v2 server metadata and server meta resouce

Change-Id: If361abaf76d13da343fd37b32b833eaf32c2ac19
Neutron apparently doesn't support PATCH

Create put_update option for services that do not support
PATCH.

Change-Id: Id558e688db447829250b95dab7e083a71cf86654
Merge "Prepare for documentation of Resources"
Merge "Neutron apparently doesn't support PATCH"