Support Resource Tags

[dgeorges]

What would you like to be added

I would like to have metadata attached to container definitions that are created by this orb in the form of aws tags. Implementation of tagging a resource can be done during its creation or after the fact.

During creation:
register-task-definition accepts a --tags argument.

After the fact:
with the tag-resource api

Either or both would be nice to be supported by this orb.

Why is this needed

This is helpful for release pipeline tracking, debugging and monitoring. Some tag that are useful could be:
'Approver' <- who approved the circleci pipeline
'GitSha' <- what code is part of this deploy.
'CreatedBy' <- tag that indicated resource created by "circle" for example.

I am sure there are other use cases.

[dgeorges]

HI,

I would like to take this issue on. I am not sure how approval works, so before I get started I just wanted to describe my planned change for review.

The update-service command will take a new parameter named task-definition-tags which will be a string in the format "key=,value=,.... If specified the task-definition will be tagged with the given tags using the aws ecs tag-resource api.

[brivu]

This has been merged in #127