(aws-ec2) Support cfn-hup

Love the recent support for cfn-init and it makes life a lot better already, but it would be great if we can add support for cfn-hup too: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cfn-hup.html

I tried to add support for cfn-hup in our application but found it very tedious to do as I will need to add a cfn-init command for the cfn-hup but it required the asg id which you cannot access at creation, I can use `asg.applyCloudFormationInit` to solve it but it just looks so hacky.

I search around in issues/pull requests but couldn't find one for this, so thought I would open one. I am happy to contribute this if no one already started.

### Use Case

cfn-hup is really useful when/if we want to update our cfn-init without replacing the host, it makes cfn-init change really easy to apply without much disruption. (e.g. installing additional yum packages)

### Proposed Solution

I proposed we build on top of the existing cfn-init solution, which should be trivial here (I think!)

### Other

N/A

* [x] :wave: I may be able to implement this feature request
* [x] :warning: This feature might incur a breaking change (breaking as in we *might* need to change userdata which will trigger host replacements, need to double check this though might not need it)

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This is a :rocket: Feature Request

Start by reading the existing cfn-init support and the asg.applyCloudFormationInit path, then review the linked AWS cfn-hup documentation. Done means cfn-hup can apply cfn-init updates to an existing host without requiring the current workaround or replacing the host.

Written by the indexing model from the issue text.