Use iam policy module instead of raw resources

[nitrocode]

Describe the Feature

To take advantage of the power of the iam_policy input of the iam policy module, it would be nice to dogfood that module within this module, use a migrations.tf here to migrate resources to the new address, and expose each of policy module's inputs here

Expected Behavior

Same behavior as upstream module without needing to reinvent the wheel

The inline policy resource should not be removed since the upstream module only supports managed policies by design

Use Case

Take advantage of upstream logic instead of recreating it

Describe Ideal Solution

See above

Alternatives Considered

No response

Additional Context

• terraform-aws-iam-role/main.tf

  Line 61 in b20978c

  resource "aws_iam_policy" "default" {

• https://github.com/cloudposse/terraform-aws-iam-policy