ARM64 support + Version bumps

[nepeat]

Addresses feature request #80 and fixes issue #90 in the process. First time contribution so I could use help figuring out how to test this.

Changes

• Split the amazon-linux-2-ami AMI into amazon-linux-2-amd64-ami and amazon-linux-2-arm64-ami
• Build ARM64 AMIs for Amazon Linux 2 for both docker + without docker
• Set server instance_type to a variable server_instance_type to allow for ARM64 support
• Nomad 0.9.1 -> 1.1.1
• Consul 1.5.1 -> 1.9.6
• Fix clean_ami_name deprecation with clean_resource_name

[hashicorp-cla]

All committers have signed the CLA.

[nepeat]

Ubuntu AMIs have failed building, trying to investigate. https://gist.github.com/nepeat/2c28bcf31c6bbda65e2fed243fe1aff2

Unsupported: The requested configuration is currently not supported. Please check the documentation for supported configurations

[nepeat]

Odd issues that resolved themselves with no new changes to the files. Logs and notes for those single failed tests below.

TestNomadConsulClusterSeparateWithUbuntu16Ami

Passes when rerun as a single test with major caveats. Test command had to be run twice to make this build and test successfully.
Log Attempt 1: https://gist.githubusercontent.com/nepeat/fb662121cd9a830a031f55641075b8bc/raw/3795cd1122b095293ce445ac29e8384f96878726/attempt_1.txt
Log Attempt 2: https://gist.githubusercontent.com/nepeat/fb662121cd9a830a031f55641075b8bc/raw/06af23cb06a882be01369b6de898f5466398b108/attempt_2.txt

TestNomadConsulClusterSeparateWith18UbuntuAmi

Passes when rerun as a single test with same major caveat as TestNomadConsulClusterSeparateWithUbuntu16Ami. I had to run the command 2 times to make this work.
Log: https://gist.github.com/nepeat/29f25412e290ad0139698b0faa7cce08

TestNomadConsulClusterColocatedWithUbuntu16Ami

Passes when rerun as a single test, no changes.
Log: https://gist.github.com/nepeat/0240912afaec916e4fc456677bd1df3f

[brikis98]

This looks great, thank you! I'll kick off tests now.

[brikis98]

Some tests failed on the first run, but I think it was due to some transient issues. They passed on re-run, so I'm going to merge!

[brikis98]

https://github.com/hashicorp/terraform-aws-nomad/releases/tag/v0.9.1