Change layout of Additional AWS Resources

[efekarakus]

As outlined in issue #915, addons templates currently don’t support Conditions.

For completeness, users can’t write Description, Metadata, Mappings, Conditions, and Transform sections into their addons template.
The only supported sections are Parameters, Resources, and Outputs.

Proposal

We propose changing the addons/ directory structure to be one CFN template per addon.
For example, if a user wants to add a DDB table and an S3 bucket addon, the file structure will be:

my-svc/
  manifest.yaml
  addons/
    mytable-ddb.yaml
    mybucket-s3.yaml

Where mytable-ddb.yaml and mybucket-s3.yaml can be full CloudFormation templates.
Behind the scenes, we will merge these two templates into one.

This should allow customers to add all the missing sections, and make it easier to write a new addon on their own.

[FarmaanElahi]

@efekarakus Is there any specific reason we are spitting this into multiple file ?

[efekarakus]

@FarmaanElahi They can all be in a single file :) Sorry, that wasn't clear enough from the description.

We're working on adding a new command storage init (#990 (comment)) that will generate CF templates under "addons/" for you. These addon commands will create a separate file each time it's run, so that we don't mess with your existing templates. Afterwards, you can move the contents to a single file if you'd like or split them up it won't matter.