Upgrade boto to boto3 in deployment scripts

[rachelekm]

Overview

Upgrades boto, used for our deployment scripts, with boto3 version 1.15.9, now at parity with boto3 used elsewhere in app.

Notes

• There's one instance where we use boto outside of deployment scripts for the app vm, here, used to add the instance IP to ALLOWED_HOSTS for the ELBs. There's currently an open issue to add a comparable method to boto3 and until then the preferred solutions seem to continue to use boto.utils or a 3rd party package, ec2-metadata. There is a describe_instances method in boto3 that looks like we can get the public IP address from, but I'm not sure which instance we should be filtering for here that would be comparable to get_instance_metadata in production. Ultimately this is a pretty narrow use case for boto and it felt worth keeping this one utility in since it's not part of our deployment.

Testing Instructions

• We're not able to test this locally since the actions affected by these updates don't actually run until launching a stack. I tried simulating launching a stack locally by manually running the action methods in a python script, but it raises a majorkirby.MKUnresolvableInputError when running the commands outside the context of a GlobalConfigNode. To test we will need to temporarily launch a web stack to confirm no issues and then delete once successful.

Checklist

• No gulp lint warnings
• No python lint warnings
• Python tests pass
• All TODOs have an accompanying issue link

Connects #1116

[rachelekm]

This method in boto had CallerReference (caller_ref) as an optional parameter and it would generate a Type 4 UUID to use by default. It is now required in boto3 and can be any unique string, so I'm continuing to use uuid by default here.

[rajadain]

+1 tested in pairing with @rachelekm. Spun up a new Green stack, confirmed that it worked, and tore it down. Great job!

Re: remaining boto issue, as long as the upcoming Python upgrades #1356 don't force an upgrade, I think it's fine to keep it.

[rachelekm]

Thanks the review and your help pairing!