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.
Check for Walrus endpoint by looking to see if the endpoint is not AWS.
This fixes a bug where the user specifies an AWS endpoint via S3_URL,
but the code interprets it as Walrus and then fails.
Migrated all examples: in DOCUMENTATION=''' string to standalone EXAMPLES=''' string
Added deprecation warning to moduledev.rst and remove deprecated example from it
Fixed up a few typos and uppercased some acronyms.
add consistency to how EXAMPLES are formatted
