Implement update of AWS::EC2::SecurityGroup

Such functionality is present on OS::Neutron::SecurityGroup
but was missing from AWS::EC2::SecurityGroup.
Updates for both Neutron and Nova-Network security groups are
implemented.

Change-Id: I86a04612567bd6080d1b825bc58acc9a08f0c2a4
Implements: blueprint handle-update-for-security-groups
Add rules output to AWS::EC2::SecurityGroup

This patch adds list of security group rules as an attribute to
AWS security group resource to allow getting their properties
as currently security group rules
are not resources in Heat themselves.

The output for both Nova-network and Neutron security groups
is converted to a common style (more resembling Nova-network
and closer to resource properties names).

Change-Id: Ia4fd7a6a291ea18d389b7484229908a376dd8cc4