645: Update EC2 instance types

[tlake]

What does this pull request do? Updates the map of EC2 instance types to memory values in common/aws/ec2/ec2.go to the current instances listed at https://aws.amazon.com/ec2/instance-types/

How should this be tested? Deploy a service on an instance that was previously not part of this list (like t3.small for example).

Checklist

• ~[ ] Unit tests~
• ~[ ] Smoke tests (if applicable)~
• ~[ ] System tests (if applicable)~
• ~[ ] Documentation (if applicable)~

closes #645