Amplify-cli: Allow option to create dynamo tables with encryption at rest enabled

[hisham]

Is your feature request related to a problem? Please describe.
Tables created by amplify cli appsync api have encryption disabled. This is one of these settings that can only be turned on when tables are created.

Describe the solution you'd like
An option in amplify to by default turn on encryption for tables. Why don't you always turn it on anyways? There's no cost to encryption at rest.

Describe alternatives you've considered
Currently have to create dynamo db tables outside of amplify cli to get this setting.

[mikeparisstuff]

This is on our backlog along with automatically enabling auto scaling for DynamoDB tables.

[mikeparisstuff]

This has since been enabled.