support nuking iam-roles

[ekristen]

This implements the ability to nuke IAM roles, but is hardcoded is ignore any AWS service or AWS reserved role and the OrganizationAccountAccessRole (default role created when using AWS Organizations)

This also adds a new config stanza that allows roles to be excluded/included just like IAM Users.

• Add Documentation for IAM Roles
• Add Tests for IAM Roles
• Add Code for IAM Roles

Since this PR #165 is stale and I needed the feature I implemented in this PR.

• Potentially Resolves New feature: ability to delete IAM roles  #131
• Potentially Resolves exclude a role when nuking #192

[denis256]

Noticed failing tests

TestCreateIamRole
TestTimeFilterExclusionNewlyCreatedIamRole

failing-test-log.txt

Since AWS API is "eventually consistent" most probably should be added retries to check IAM role got created

[brikis98]

Important note: we run cloud-nuke against several Gruntwork accounts, and those accounts have IAM roles that we use to access them, so we want to be sure we don't accidentally nuke those very IAM roles! Please make sure to double check the config in https://github.com/gruntwork-io/cloud-nuke/blob/master/.circleci/config.yml#L32-L62 won't blow away those IAM roles before merging.

[svenfinke]

What is the status with this PR? It would be great if roles are included in the nuke!

[ddvdozuki]

Yea, this is a huge feature I've been waiting on. Hopefully it gets reviewed and merged soon. Cloud nuke leaves behind many resources that are not yet supported :(

[zackproser]

@ekristen I adopted your changes into #330 and released it here: https://github.com/gruntwork-io/cloud-nuke/releases/tag/v0.14.0

Thank you for your contribution!