Move aws checks to aws plugin

[eheydrick]

A few checks in http use aws-sdk to check S3. That functionality should move to the aws plugin to minimize dependencies in the http plugin and keep AWS checks together. The checks should be copied to the aws repo, deprecated here, and then removed in a future major release.

[tmonk42]

I just took a look at this. The current version of these two checks work just fine with no AWS integration. The AWS component is an optional way to add in more config json to the check. See https://github.com/sensu-plugins/sensu-plugins-http/blob/master/lib/sensu-plugins-http/common.rb#L21 if it's configured, this will go out to S3, fetch some json, and then merge it with the check config.

I don't think we want to move these checks over to the sensu-plugins-aws repo. These are very traditional HTTP checks, just two of them have some extra sauce for being able to include extra config info from S3.

[majormoses]

I think we should remove that functionality as thats quite a bit of extra deps pulled in for arbitrary config injection. This would need to be called out in the changelog with a ### Breaking Changes header and would be released as a major version.

[tmonk42]

We might need to retain the aws-sdk dependency for V4 signing. I'll dig into this a bit more soon.

[majormoses]

If we want we can still remove it: https://docs.amazonaws.cn/en_us/general/latest/gr/signature-v4-examples.html#signature-v4-examples-ruby alternatively we could try just including the core SDK: https://github.com/aws/aws-sdk-ruby/blob/97b28ccf18558fc908fd56f52741cf3329de9869/gems/aws-sdk-core/lib/aws-sdk-core/plugins/signature_v4.rb which would at least reduce the number of dependencies pulled in.