Implement ansible.module_utils.rax

Added `-y` flag to `query_package`

Exit 0 with no matched hosts

New library/cloud/ec2 module parameter (assign_public_ip) for non-default VPC instance launching.

Fix "manual" ansible-playbook example in guide_vagrant.rst

The given example is trying to load an inventory file with the -i option, so it should probably be given the actual Vagrant-written inventory file name. I contemplated using 'vagrant_ansible_inventory_default' instead (which is what my Vagrant demo actually creates) but 'vagrant_ansible_inventory_machinename' is more consistent with the existing example in the docs.

Add PyPi version badge.

Fix for documentation playbook loops

mention that the mount module will remove mount directories

Fixes #5081

Correct the invocation of ‘_assemble_from_fragments’

Code to limit display of version_added attributions in modules for modules that are too old to call out this information.

This does not generically apply to new arguments added to existing modules, just the version_added attribute on the top level modules.

Revert "No longer need to reference 'version_added' in docs for these, as this was quite a while ago."

This reverts commit ff0a41d4.

Docs: Fix the module formatter code that is intended to remove the 'historical' variable from showing up in version_added information (RST)

Avoid a traceback when using accelerate

fix heading name syntax in AWS guide

This bit of code is attempting to access accelerate_inventory_host,
which may not have been set/created. This will cause a traceback.
Instead use getattr with a fallback to False.

Fixes #5064

Fix AWS credential params for ec2_ami, ec2_elb, ec2_tag, ec2_vpc, route53, and s3 modules

if key is used with lookup parameter needs quotes as
otherwise it will load "ssh-rsa" "<the key>" "<the comment>" as separate
values and fail with "this module requires key=value arguments"

fixed documentation typo about region purpose

if key is used with lookup parameter that needs to be in quotes as
otherwise it will load "ssh-rsa" "<the key>" "<the comment>" as separate
values and fail with "this module requires key=value arguments"

The `ec2_ami`, `ec2_elb`, `ec2_tag`, `ec2_vpc`, `route53`, and `s3` modules
all canonicalize the AWS access and secret key params as
`aws_access_key` and `aws_secret_key`. However, following the fixes for #4540,
those modules now use `get_ec2_creds` from `lib/ansible/module_utils/ec2.py`,
which requires access/secret key params to be canonicalized as
`ec2_access_key` and `ec2_secret_key`. As a result, AWS credentials passed
to those six modules as parameters are ignored (they instead always use
the AWS credentials specified via environment variables, or nothing).

So this change fixes those six modules to canonicalize the
AWS access and secret key params as `ec2_access_key` and `ec2_secret_key`,
allowing them to again accept AWS credentials passed via module params.

fixed typo for assemble function