Fixes #7910

Default is set to 300 seconds, which is AWS default.

This PR fixes a bug (#7898) where instances created within an autoscaling group using the `ec2_asg` module gets immediately terminated because the `health_check_period` is set to 0, which causes the instance to be checked without having the time to actually boot.

Adding `health_check_type` is needed because you may want to check your instance health against an ELB instead of just EC2 default cloudwatch.

  - Added a more verbose response
  - includes its settable attributes and a list of its instances.
  - allows setting of tags, changes upon which mark the task changed
  - allow getting of information from asg module, not just setting
  - doesn't mark changed if the parameter wasn't specified
  - Availability Zones are pulled from the region

Fixes #7505

Created common module doc fragment, and applied to all
modules that use ec2_connect or connect_to_aws as
they definitely share the common doc fragments

* Added desired_capacity and vpc_zone_identifier to ec2_asg
* Use ec2_argument_spec() method and then remove unnecessary
  declarations from argument_spec
* Remove AWS_REGIONS declaration
* Rename block_device_mappings to volumes to be consistent with ec2
* Remove all pep8 warnings except line length and continuation indent
* Use updated module_utils/ec2.py to add profile and security_token
  support
* Remove mandatory arguments for delete to make launchconfig deletion
  work
* Handle existing launch configurations better
* Improve output information
* Improve documentation

Includes management of Launch Configuration and related Autoscaling
Groups