Re-generate documentation fixtures.
Modify fixture generation script to treat list_records and list_zones as
implemented if iterate_records and iterate_zones method is implemented.

Also fix the script to preserver correct order.
Don't include local storage provider in the supported providers table.
Re-generate supported providers and supported provider methods table.
Update .gitignore.
Add new KeyPair class and methods for the key pair management to the NodeDriver
class.
Update existing compute drivers (OpenStack, CloudStack, EC2) which expose key
pair management through the extension methods to expose it through a new
standard key pair management API.

Also update affected code and tests, deprecate existing extension methods and
add some missing tests.

Note: Old and now deprecated methods will work until a next major release.
docs: Update upgrade notes,  add a new section about key pair management
and update existing docs.
Add and implement get_key_pair method.

Also add tests and update documentation.