Cloudbridge

---------------------------------------------------------------------

* Use external non-shared network for gateway by almahmoud in https://github.com/CloudVE/cloudbridge/pull/307
* Install cloudbridge full in examples by nuwang in https://github.com/CloudVE/cloudbridge/pull/310
* Add new `ec2_retries_value` config for `AWSCloudProvider` by MosheFriedland in https://github.com/CloudVE/cloudbridge/pull/313
* Add packaging action by nuwang in https://github.com/CloudVE/cloudbridge/pull/314
* Fix linting error in resource comparison by nuwang in https://github.com/CloudVE/cloudbridge/pull/315
* Fix tox syntax and branch references by nuwang in https://github.com/CloudVE/cloudbridge/pull/316
* Switch to pytest by nuwang in https://github.com/CloudVE/cloudbridge/pull/317
* Update tox syntax and pin min tox version by nuwang in https://github.com/CloudVE/cloudbridge/pull/318

---------------------------------------------------------------------

* Added app credentials support to openstack.
* Added VM instance create time property to all providers (thanks to rodrigonull)
* Added Azure stop VM instance method (thanks to rodrigonull)
* Cloud provider sdks updated to latest versions
* Other misc fixes.

---------------------------------------------------------------------

* This is a major release due to packaging changes, although there are no backward incompatible interface changes.
* The cloudbridge package no longer installs any providers by default, and you must use `pip install cloudbridge[full]`
instead of `pip install cloudbridge` to obtain previous behaviour. This is to allow greater control over what
providers are installed. To install only specific providers, use `pip install cloudbridge[aws,gcp]` etc. 292
(thanks to RyanSiu1995)
* Allow users to create signed urls with write permissions 294 (thanks to FabioRosado)

---------------------------------------------------------------------

* This is a maintenance release with no backward incompatible changes.
* Azure dependencies updated to latest version and associated fixes 274, 277, 278, 279, 281, 282
(thanks to FabioRosado)
* AWS, GCP and OpenStack dependencies updated to latest versions and associated fixes.
* AWS resources use TagSpecification support, removing extra requests for initial tagging.
* Fixed wrong logging object in cloud provider 272 (thanks to MosheFriedland)
* Switched to github actions from travis
* Patch discovery.build calls in GCP provider to use google's improved httplib2 263 (thanks to selshowk)
* Added feature to start and stop aws instance 271 (thanks to abhi005)
* Miscellaneous doc and maintenance fixes.

---------------------------------------------------------------------

* This release introduces the DNS service, which is a top level service for managing DNS zones and records.
* Support for using the newly added AWS instance type offerings API. This removes the dependency on a static machine
type list, and returns up-to-date information on instance type availability.
* The default package no longer bundles Azure, as the Azure python libraries are very large and affects docker
container size when using cloudbridge. To install with Azure, use `pip install cloudbridge[full]` or
`pip install cloudbridge[azure]`.
* A convenience method for cloning providers in different zones has been added, which helps with multi-zone operations.
* Support for specifying s3 signature version for the AWS provider.
* Miscellaneous bug fixes and error handling improvements.
* Support for python<3 dropped.
* No major backward incompatible changes (apart from Azure not being bundled by default)

---------------------------------------------------------------------

* This is a major release which contains many improvements and some breaking
changes to the interface, but the changes are fairly straightforward.
* Support for Google Cloud (thanks to mbookman, chiniforooshan, baizhang)
* Support for middleware, event listening and interception, allowing
CloudBridge to be extended without needing to modify library code (This is
also potentially useful for handling corner cases for specific clouds).
* The mock provider is now available by default as a standard cloud provider,
which is useful for testing applications that use CloudBridge.
* Providers now operate in a single zone, and therefore, all methods that
previously required the zone as a parameter no longer do. Specifically,
``instance.create()``, ``volume.create()``, ``subnet.create``,
``subnet.get_or_create_default()`` are affected in services,
and ``snap.create_volume`` is affected in resources. The provider's default
zone must now be specified through the provider config.
* All exceptions that are generated by CloudBridge will now extend from
``CloudBridgeBaseException``
* The cloud package is deprecated and everything under it has been moved
one level up. For example, instead of
``from cloudbridge.cloud.factory import CloudProviderFactory`` use
``from cloudbridge.factory import CloudProviderFactory``.
* Services are much more uniform now, and sub-services have been introduced
for greater uniformity. For example, ``net.create_subnet()`` is now
``net.subnets.create()``
* ``gateways.get_or_create_inet_gateway()`` is now simply
``gateways.get_or_create()``
* AWS instance types are now served through Amazon CloudFront for better
performance.
* Miscellaneous bug fixes and improvements.