Leverage aws_partition data source instead of ever manually specifying "arn:aws:..."

[rfairburn]

This will help allow us to support govcloud without needing forks or recommended changes. While there may be additional things, this will solve a known breakage.

Known files to have "arn:aws" at the time of this writing:

addons/byo-file-carving/target-account/s3.tf
addons/byo-firehose-logging-destination/target-account/firehose.tf
addons/cloudfront-software-installers/main.tf
addons/logging-alb/main.tf
addons/mdmproxy/iam.tf
addons/monitoring/main.tf
byo-vpc/byo-db/byo-ecs/iam.tf

[waffleoffagus]

Hi! I was one of the customers that raised this - any plan for updating this? With data lookups this shouldn't be a breaking change for most.

[rfairburn]

#235 has the changes necessary to support aws partitions other than arn:aws... I'm going to submit it for review/approval today. It passed all of my checks.

The one module completely uncovered at this point is using cloudfront for software installers because cloudfront doesn't exist in govcloud. Cross-partition integration that includes the signed URLs is outside of the scope of what I could get out the door in this PR.

Software installers will still work via the normal s3 -> Fleet -> client methodology.

Once this PR merges, I'll have a separate PR updating our examples to leverage the newly tagged module versions. I'll comment on it here as well.

[rfairburn]

With #239 merged, all examples should have the versions of the modules that use aws_partition fully. To the best of my knowledge GovCloud should be a valid deployment target now.