ENA support for AWS provider

[hardikdr]

What would you like to be added:
We have been requested to add support of ENA for eligible instance-types.

The detailed documentation around how to enable the support can be found here: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/enhanced-networking-ena.html

GardenLinux is already adapted to have necessary drivers in the AMI, hence nothing needs to be done.

The requirement for other OSes and overall scope is yet to be discussed.

[hardikdr]

cc @marwinski @vpnachev

[rishabh-11]

@vpnachev @marwinski is this feature still required? If not, we would like to close the issue

[vpnachev]

🤷